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The Complete Guide to AP Environmental Science FRQs

Posted by Christine Sarikas | Nov 4, 2018 9:43:00 AM

Advanced Placement (AP)



AP Environmental Science is one of the most popular AP classes, but it has the lowest average score among test takers. In fact, more than half of students who take the exam don’t pass it. Oftentimes, the hardest part of the exam is the free-response section which students struggle with because they aren’t sure what to expect or what information graders are looking for. Fortunately, this guide can help.

I’ll go over each type of AP Environmental Science FRQ, give sample problems and explanations, and end with tips you should follow in order to get your best score.


What’s the Format of the AP Environmental Science Free-Response Section?

On the day of the AP exam, your test will have two sections. First, you will have 90 minutes to answer 100 multiple-choice questions, then you’ll move onto the free-response section.

Here's the format of the free-response section:

  • 90 minutes total
  • No calculator allowed
  • Includes four questions:
  • 1 document-based question
    • The document-based question will give you a document or an excerpt from a document and ask you questions based on information it contains. The document can be a newspaper article, brochure, or something similar.
  • 1 data set question
    • This question will include data you must analyze and interpret. The data may be in a table, graph, chart, or stated within the question. Parts of the question will require calculations; parts will not.
  • 2 synthesis and evaluation questions
    • These are similar to the document-based question, except they won’t include outside documents. They sometimes include graphs or tables, however, you won’t be expected to do calculations for these types of questions.
The free-response section is worth a total of 40% of your score. Most questions are worth 9-11 points, but each question is weighted equally, so each of the four questions will be worth 10% of your final score.

In the free-response section, you’re expected to show reasoning and analytical skills, as well as the ability to synthesize information from multiple sources into coherent essays.


AP Environmental Science FRQ Examples

Below are each of the three types of free-response questions you’ll see on the AP exam. For each question, I’ll go through the answer step-by-step so you can see how points are earned.


Document-Based Question



 You’ll know the document-based question because it is typically the first question asked and it’ll have that “torn piece of paper” graphic you see above. Fortunately, compared to many other AP tests, the documents on AP Enviro exams tend to be quite short and there’s only one, so you should be able to read through it quickly. In this case, it looks like the document is part of an article from the Fremont Examiner that was printed in May 2013. 


Part A:

Part A is worth four points: You’ll earn a point for each of the two activities you list and a point for each of the two explanations you give on how the activity alters sediment flow.

In order to earn the full four points, the two activities must be reasonable human activities that can alter natural sediment flow, and your explanations must accurately explain how each activity would change the flow of sediment.

There are a lot of different answers you could put; here’s a sample answer:

Activity 1: Building Dams. Effect on flow of sediments: Building dams could block the flow of sediments from upstream, which would then decrease the sediment downstream of the dam and potentially starve the coast of nutrients. Building dams can also prevent flooding that would allow sediment to be deposited on the floodplain as well as decrease increase flow velocity which can increase erosion downstream.

Activity 2: Water Extraction. Effect on flow of sediments: Overuse or over pumping of water can reduce river flows, which in turn decreases the sediment load to the Gulf.

Note that you don’t have to write complete paragraphs for every question. It’s enough to clearly label the different parts of your answer and give a thorough explanation.


Part B:

Part B is worth two points, one point for each description. (Be aware that they’re asking for ecological impacts, not economic impacts).

A potential answer could be:

1. Loss of coastal habitats that certain plant and animal species need to survive

2. Increased flooding of coastal wetlands due to the loss of beaches and barrier islands

For this answer, you don’t even need to give complete sentences. For the free-response section, don’t add a lot of fluff to your answers thinking it’ll raise your score. Graders are looking for specific points, and the easier you make it to find your answers, the easier they’ll be able to award you points.


Part C:

Part C has three different parts within it; let’s break them down one by one.

(i) This part is worth two points, and you get them just by listing two environmental impacts fertilizer has on the Gulf of Mexico’s marine ecosystem. Potential answer: Increased algae growth and lower dissolved oxygen

(ii) This is almost the same as the above question, except now you’re listing economic instead of environmental impacts. Potential answer: decreased property values and increased seafood prices due to lower seafood supply.

(iii) For the final part of this question, worth one point, you have to give a strategy to reduce the flow of nutrients into the Mississippi River (besides reducing fertilizer). Potential answer: Add green roofs to reduce runoff.

As you’ve probably noticed, document-based questions are pretty straightforward and can usually be answered in a few words or a sentence or two. The key is to pay attention to exactly what the question is asking, going into enough depth to completely answer the question, and making it easy for graders to find each of your answers to the different parts of the question.



Make it easy for the graders to find your answers.


Data Set Question

This is when you'll need to do some calculations. As a reminder, no calculator is allowed on this exam. The good news is that this means that the calculations you’ll need to complete will likely be much simpler than those of other AP science exams. Typically, you’ll only need to complete simple algebraic expressions to solve the problem.



Part A:

For the first part of this question, worth two points, you don’t need to do any calculations; you just need to list two pollutants that fit the description in the question.

Examples: fertilizers, animal feces, pesticides, gasoline, road salts, etc.


Part B:

Here’s where you’ll complete your first calculation. You can earn one point for correctly setting up the question (so be sure to show your work!) and one point for the correct answer.

This is a basic volume question. To answer it, you’ll need to know that the volume of a rectangular solid (which is roughly the shape of most parking lots) is length * width * height.

From the question, we know that length= 200m and width=100m, and since we’re calculating based on a 5cm rainfall, width = 5cm. However, these measurements don’t all have the same unit! Before we calculate volume, we have to convert 5cm to meters.

5cm * (1m/100cm)= 0.05m

Since there are 100 cm in a meter, this is a pretty simple calculation, but don’t be tempted to skip it and just write down .05m. Be sure to show your work! If you don’t, you won’t get the maximum number of points.

Now that we have all the pieces of info we need, with the correct units, we can plug those numbers into the volume equation:

V= 200m * 100m * .05m = $\1000m^{3}$


Part C:

You’ll need to complete another volume calculation for this part. This question wants to know the volume of runoff for the entire community, not just the parking lot. As in Part B, this question is also worth two points, one for correctly setting up the question and one for giving the correct answer.

We’ll still use our handy V=lwh equation to find the volume of a rectangular solid.

We know that the area of Fremont (so length * width) is $\10km^{2}$  , which we’ll need to convert to $\m^{2}$

$\10km^{2}$ * ($\1,000,000m^{2}$/1 $\km^{2}$) = $\10,000,000m^{2}$

We know that height is still .05m, based on part B, so now we can plug our numbers into the volume equation.

V = $\10,000,000m^{2}$  * .05m = $\500,000m^{3}$

But, we’re not done yet! Remember, only 20% is covered by impervious surfaces, which we are told to assume are the only areas that generate runoff. So, first, we have to figure out the area of impervious surfaces in Fremont. This just involves finding 20% of Fremont’s total volume:

$\500,000m^{3}$ * 0.2= $\100,000m^{3}$


Part D:

Part D is worth one point, and, to get that point, you have to give the correct answer with your work shown. This is another question about volumes, but you don’t need to calculate any volumes this time, you just have to do some simple addition and subtraction.

Since the treatment plant can treat up to $\10,000m^{3}$ of sewage and storm water a day, and it receives $\5,000m^{3}$ of sewage daily, the runoff that bypasses the plant is the amount of total runoff plus the $\5,000m^{3}$ of regular sewage minus the $\10,000m^{3}$ that would get treated.

Runoff that bypasses the plant = Total runoff + $\5,000m^{3}$ - $\10,000m^{3}$

We calculated runoff from the parking lot and the community in part c ($\100,000m^{3}$), so we just need to plug that value in.

Runoff that bypasses the plant = $\100,000m^{3}$ + $\5,000m^{3}$ - $\10,000m^{3}$  = $\95,000m^{3}$ 


Part E:

Possible answers:

  • Create wetlands to absorb storm water
  • Install rain barrels and cisterns to collect storm water
  • Install green roofs or rooftop gardens to use storm water


Part F:

To earn part F’s one point, you must give an environmental problem that occurs when there are extensive paved areas.

Possible answers:

  • Erosion caused by flooding or excess runoff
  • Habitat destruction caused by the removal of vegetation



Hopefully this sewer is better-prepared for storm water than Fremont's sewer system is.


Synthesis and Evaluation Question

As a reminder, there are two synthesis and evaluation questions on each AP exam. Here's an example of one: 



Part A:

You can earn up to two points, one for each characteristic. Possible answers: Complex food webs,  greater genetic diversity, large number of different species


Part B:

Part B is worth four points, one point for each activity you provide (up to two) and one point for correctly explaining how each activity results in a loss of biodiversity.

Note that you’ll have to use your answers for this part to come up with your answer for part C, so you may want to take that into account when you’re thinking about which activities to list. This is part of the reason why skimming through the entire question before you begin answering can be very helpful!

Possible answers:

Activity 1: Logging/deforestation. Explanation: Reduces habitat for many species and causes habitat fragmentation.

Activity 2: Introduction of invasive species. Explanation: Displaces native species.


Part C:

Here you can earn two points, one for each reasonable solution you give for the activities you listed in part b.

Possible answers:

Activity 1: Logging/deforestation. Solution: Replant trees; engage in selective cutting.

Activity 2: Introduction of invasive species. Solution: Create checkpoints for agricultural inspections; create stricter laws on the import of exotic species.


Part D:

To earn the one point for part D, you need to correctly describe a naturally occurring factor that could lead to a loss of biodiversity.

Possible answers:

  • Wildfires can wipe out small populations
  • Hurricanes/tsunamis can destroy estuaries and coastal ecosystems
  • Droughts can cause some species to lose their food sources


Part E:

Part E is worth two points, one for each ecological benefit you list.

Possible answers:

  • Greater control of pest species
  • Water filtration by intact ecosystems
  • More source material for evolution



Here's a pest you'd probably like to control.


Tips for Solving AP Enviro Free-Response Questions

The AP Environmental Science FRQs often trip students up, and, for most questions, the average score is 30-40%. Below are some tips you should keep in mind while studying as well as when you’re taking the test to help you improve your chances of scoring well on this section.


1. Figure Out How Long You Want to Spend on Each Question Before You Begin

You will have 90 minutes to complete the entire free-response section, which gives you about 22 minutes per question. However, you don’t need to spend exactly the same amount of time on each question. In fact, you can divide your time between the four essays any way you want.

Some people spend longer on the data set question due to the calculations involved, while others find that the quickest question and take longer to answer questions that require complete sentences or paragraphs. You may spend 15 minutes on one question and close to a half-hour on another.

The best way to learn which questions take you longer is to complete a lot of practice problems, which we’ll discuss in the next section. Once you’re comfortable with each type of free-response question, you can go into exam day knowing about how long you want to spend on each question.

Also, you absolutely don’t have to answer the questions in order. When you start the section, give them a quick look-through and decide which one you’d like to answer first. A lot of people choose to start with the question they are most confident with so that they’ll (hopefully) have extra time at the end for questions they find trickier.


2. Be Comfortable Solving Equations Without a Calculator

AP Environmental Science is the only AP science exam where you cannot use a calculator for the free-response section, which includes the data set question. As you saw above, none of the calculations you’ll need to do are particularly tricky, but if you’re slow at mental math, you could waste a lot of time you’ll need to complete the three other questions in this section.

Once again, the best way to prepare for this is to practice. Complete plenty of data set practice problems without a calculator so that you get used to quickly doing math by hand. You don’t want all your hand-earned knowledge to be wasted come test day when you find yourself struggling to solve equations.


3. Keep Your Units Straight

My final tip also applies primarily to the data set question. As you saw in the sample problem, questions often include multiple types of units. The sample problem had centimeters, meters, and kilometers. Making a careless error and reading “5cm” as “5m” will cost you points on the exam.

When you take the test, be sure to pay attention to every unit that you see. Circle or underline the units if you have to in order to make them stand out. Also, you should be a pro at converting between units. You don’t want to waste time trying to remember how many meters are in a kilometer; it should be something you know off the top of your head.

Now, even after you’ve become a unit expert, don’t forget to show your work when you convert from one unit to the next. Even if the process of going from meters to kilometers seems ridiculously obvious to you and doesn’t seem like it warrants being written out, do it anyway! Typically, half the points you earn on calculation problems are from showing your work, so don’t let a bit of laziness lower your score.


How to Practice Free-Response Questions

After reading this far, you now know all the basics of the AP Environmental Science free-response section. However, the way to really conquer the test and get a high score is to become an expert! How can you do that? The best way is to complete lots of practice problems.

On their website, the College Board has links to all the previously given free-response questions for exams from 1999-2015. That means you have dozens of official free-response questions to look over and practice. Because there are so many free-response problems, you can begin completing practice problems a few months into your class (say around November) and continuing up until the AP exam.

At the beginning of the year, when you’re still learning a lot of the course material, you can read through the questions to find the ones that focus on topics you’ve already covered. In order to get the most of these practice problems, use a timer and give yourself the same timing limitations the real exam will have. Also, no calculator!



The free-response section of the AP Environmental Science exam is often challenging for students, but becoming familiar with it can go a long way to helping you get a higher score.

The free-response section contains four questions:

  • 1 document-based question
  • 1 data set question
  • 2 synthesis and evaluation questions

You’ll have 90 minutes to complete this section, and it’s worth 40% of your total score. Also, no calculators are allowed.

To maximize your chances of doing well keep these three tips in mind:

  • Figure out how long to spend on each question before you begin
  • Be comfortable solving equations without a calculator
  • Keep your units straight

Also, remember to complete lots of practice problems so you’ll feel confident and prepared on the day of the exam.


What's Next?

Want some more practice materials for AP Enviro? We've got 'em! Check out our guide with links to every AP Environmental Science practice test and quiz available online (coming soon).

Now you know what the free-response section will be like, but how do you review for AP Enviro? Our guide walks you through each step of creating a study plan that will pinpoint what you need to study.

Wondering when you should start studying for AP Enviro and other AP exams? In our guide, we help you figure out exactly when you need to start cracking open those review books.


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Christine Sarikas
About the Author

Christine graduated from Michigan State University with degrees in Environmental Biology and Geography and received her Master's from Duke University. In high school she scored in the 99th percentile on the SAT and was named a National Merit Finalist. She has taught English and biology in several countries.

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