Should You Take the SAT Biology E or M Test?

A close up view of a person taking the SATs.


The SAT Biology E and M tests are two of 20 subject exams offered by the College Board. Although not all colleges and universities require SAT subject tests for admission, some do require them for specific majors or offer course credit if you score well enough. These tests are also useful for assessing your knowledge of science, math, English, history, and languages.

The Biology E and M Tests

The College Board offers subject tests in three scientific categories: chemistry, physics, and biology. Biology is subdivided into two categories: biology ecology, known as Biology-E, and molecular biology, known as Biology-M. They are two separate tests, and you cannot take them both on the same day. These tests are not part of the SAT Reasoning Test, the popular college admissions exam. 

Here are some basics you should know about the Biology E and M tests:

  • Each test is timed, lasting 60 minutes, and contains 80 multiple-choice questions.
  • 60 of the 80 questions are found on both exams, with the other 20 unique to each test.
  • Scoring ranges from 200 to 800 points in total.
  • Calculators may not be used for the exam, except for Math 1 and Math 2 tests.
  • The metric system is used for all measurements in test questions.
  • The College Board recommends having at least one year of college-prep biology, plus a year of algebra, and experience in a classroom laboratory setting.

Is the Biology E Test Easier?

Questions on both the Biology E and M exams are divided evenly between fundamental concepts: identifying terms and definitions, interpretation (analyzing data and drawing conclusions), and application (solving word problems). The College Board recommends students take the Biology E test if they are more interested in topics such as ecology, biodiversity, and evolution. Students more interested in topics such as animal behavior, biochemistry, and photosynthesis should take the Biology M exam. 

The College Board offers a comprehensive list of institutions that require or recommend SAT subject tests on their website. It's also a good idea to check with your college admissions officer to confirm whether or not these tests are required.

Test Categories

The Biology E and M tests cover five categories. The number of questions on each exam varies according to the topic.

  • Cellular and molecular biology (Biology E, 15 percent; Biology M, 27 percent): Cell structure and organization, mitosis, photosynthesis, cellular respiration, enzymes, biosynthesis, biological chemistry.
  • Ecology (Biology E, 23 percent; Biology M, 13 percent): Energy flow, nutrient cycles, populations, communities, ecosystems, biomes, conservation biology, biodiversity, effects of human intervention.
  • Genetics (Biology E, 15 percent; Biology M, 20 percent): Meiosis, Mendelian genetics, inheritance patterns, molecular genetics, population genetics.
  • Organic biology (both 25 percent): Structure, function, and development of organisms (with emphasis on plants and animals), animal behavior.
  • Evolution and diversity (Biology E, 22 percent; Biology M, 15 percent): Origin of life, evidence of evolution, patterns of evolution, natural selection, speciation, classification and diversity of organisms.

Preparing for the SAT

Experts at the Princeton Review, an established test-prep organization, say you should begin studying at least two months before you plan to take an SAT subject test. Schedule regular sessions each week for at least 30 to 90 minutes, and be sure to take breaks as you study.

Many of the major test-prep companies offer free sample SAT subject tests. Use these to evaluate your skills before you begin studying and at least a couple times prior to taking the actual exams. Then, check your performance against the average scores provided by the College Board.

All of the major test-prep companies also sell study guides, offer classroom and online review sessions, and provide tutoring options. Be aware that the price for some of these services can cost several hundred dollars.

Test-Taking Tips

Standardized tests like the SAT are designed to be challenging, but with preparation, you can succeed. Here are some tips that testing experts recommend to help you get the best scores possible:

  • Schedule tests, particularly science and math, for as soon as possible after you've finished your relevant high school coursework. This way, the knowledge will be fresh in your mind.
  • The test is offered five times a year: May, June, August, October, and December. Register early so you'll be able to take the test well ahead of when results are due for college admissions.
  • Confirm your admission status. Whether you register online or by mail, you'll receive an "admissions ticket" that lists your test time, location, and date. Check to make sure all the info is correct; if not, call the College Board.
  • Make sure you have the right test materials. You'll need to bring your admissions ticket to the testing site to confirm your registration. You'll also need a photo ID, as well as two No. 2 pencils and a durable eraser.
  • Pace yourself. Remember, you only have 60 minutes to complete the exam. Do the easy questions first, then circle back to those that challenge you. If you find yourself running low on time, don't be afraid to make an educated guess on questions that you're stuck on.
  • Get plenty of rest the night before. Tests like the SAT are intellectually demanding. You'll want to be fresh and alert when you take the tests.

Sample SAT Biology E Question

Which of the following individuals is most fit in evolutionary terms?

  • (A) A child who does not become infected with any of the usual childhood diseases, such as measles or chicken pox.
  • (B) A woman of 40 with seven adult offspring.
  • (C) A woman of 80 who has one adult offspring.
  • (D) A 100-year old man with no offspring.
  • (E) A childless man who can run a mile in less than five minutes.

The answer B is correct. In evolutionary terms, fitness refers to an organism’s ability to leave offspring in the next generation that survives to pass on genetic traits. The woman of 40 with seven adult offspring has left the most surviving offspring and is the most fit evolutionarily.

Sample SAT Biology M Question

Which of the following most accurately reveals common ancestry among many different species of organisms?

  • (A) The amino acid sequence of their cytochrome C.
  • (B) Their ability to synthesize hemoglobin.
  • (C) The percentage of their body weight that is fat.
  • (D) The percentage of their body surface that is used in gas exchange.
  • (E) The mechanism of their mode of locomotion.

Answer A is correct. To assess common ancestry among organisms, differences or similarities in homologous structures are studied. Differences in homologous structures reflect the accumulation of mutations over time. The only choice listed that represents a comparison of a homologous structure is choice (A). Cytochrome C is a protein that can be studied, and its amino acid sequences compared. The fewer differences in the amino acid sequence, the closer the relationship.


Unknown. "Subject Tests in Science." The College Board, 2019.

Franek, Rob. "Which SAT Subject Tests Should I Take?" Princeton Review.

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Roell, Kelly. "Should You Take the SAT Biology E or M Test?" ThoughtCo, Apr. 5, 2023, Roell, Kelly. (2023, April 5). Should You Take the SAT Biology E or M Test? Retrieved from Roell, Kelly. "Should You Take the SAT Biology E or M Test?" ThoughtCo. (accessed May 31, 2023).