CLEP Biology Exam Prep 2026 practice questions and answers. Tap an option to test yourself — you'll see the correct answer and a plain-English explanation for every question. Free, no login.
Q21Biologist Contribution Field of Study Watson and Crick DNA structure Genetics Gregor Mendel Laws of inheritance Heredity Charles Darwin Theory of evolution Natural selection Rosalind Franklin X-ray diffraction DNA research Based on the table above, which contribution by Rosalind Franklin was crucial in the study of DNA, complementing Watson and Crick's model?
✓ Correct answer: B. X-ray diffraction
Rosalind Franklin's use of X-ray diffraction provided key evidence for the helical structure of DNA, supporting Watson and Crick's model of the double helix.
Q22In flowering plants, from which tissues does a fruit typically develop?
✓ Correct answer: D. From the ovary tissue after fertilization
Answer: From the ovary tissue after fertilization In flowering plants, the fruit typically develops from the ovary tissue post-fertilization. The ovary swells and matures to form the fruit, which serves as a means to protect and disperse the seeds within.
Q23Refer to the table below and identify which nutrients are essential for animals to obtain from their diet. Nutrient Requirement for Animals Source Proteins Essential Diet Carbohydrates Non-essential Generated by digestion Vitamins Essential Diet Cholesterol Non-essential Synthesized by liver Minerals Essential Diet
✓ Correct answer: C. Proteins, Vitamins, and Minerals
Answer: Proteins, Vitamins, and Minerals Proteins, vitamins, and minerals are necessary for animals as they cannot synthesize them and must obtain them from their diet. In contrast, carbohydrates can be produced by breaking down other nutrients, and cholesterol is synthesized by the liver.
Q24In mammals, what primarily regulates the circadian rhythm, often referred to as the biological clock?
✓ Correct answer: B. Suprachiasmatic Nucleus
Answer: Suprachiasmatic Nucleus The suprachiasmatic nucleus (SCN) located in the hypothalamus is responsible for controlling circadian rhythms in mammals. It coordinates the body's internal clock by regulating hormone release and responding to environmental cues such as light.
Q25What passes through the gastroesophageal sphincter?
✓ Correct answer: A. Bolus
Answer: Bolus A bolus is a ball-like mixture of food and saliva that travels from the mouth to the stomach. It passes through the gastroesophageal sphincter (or cardiac sphincter) before entering the stomach for digestion.
Q26In mammals, how does sperm reach the egg during fertilization?
✓ Correct answer: C. During mating, sperm are deposited near the cervix and travel through the cervix into the uterus. They continue into the fallopian tubes where fertilization of the egg occurs.
Answer: During mating, sperm are deposited near the cervix and travel through the cervix into the uterus. They continue into the fallopian tubes where fertilization of the egg occurs. The process usually begins with mating, during which sperm are transferred from the male to the female. The sperm travel through the female's reproductive tract, entering the cervix and progressing into the uterus. From there, they continue into the fallopian tubes. It is within the fallopian tubes that the sperm encounter the egg (if present), and fertilization happens when a sperm penetrates and fuses with the egg.
Q27Which organisms can be classified as contributing significantly to the ecosystem's nutrient cycling through decomposition? Organism Type Function in Ecosystem Fungi Decomposes organic material Bacteria Breaks down organic material Plants Produce oxygen and food Predators Control prey population
✓ Correct answer: D. Fungi and Bacteria
Fungi and bacteria play a crucial role in nutrient cycling as they break down dead organic material, returning nutrients to the soil and enabling plant growth. Plants and predators do not perform decomposition functions. Plants contribute to the ecosystem by producing oxygen and serving as a food source.
Q28Examine the table below to identify which structures are part of the central nervous system and involved in processing sensory information. Structure System Function Cerebrum Central nervous system Sensory/motor processing Medulla oblongata Central nervous system Autonomic functions Olfactory lobes Central nervous system Smell processing Optic nerves Peripheral nervous system Vision transmission Cerebellum Central nervous system Balance and coordination
✓ Correct answer: C. Cerebrum, Olfactory lobes
The cerebrum is part of the central nervous system and plays a crucial role in sensory and motor processing. The olfactory lobes, also part of the central nervous system, are specifically involved in processing smell. Optic nerves are part of the peripheral nervous system, and while the medulla oblongata and cerebellum are central, they are more involved in autonomic functions and balance, respectively.
Q29When you twist your ankle, which type of tissue is primarily affected?
✓ Correct answer: A. Ligament
Answer: Ligament Ligaments are the fibrous tissues that connect bones to other bones in joints. A twisted ankle typically involves stretching or tearing of ligaments within the joint.
Q30Examine the life cycle of angiosperms below. Which process results in the formation of fruit? Process Description Pollination Transfer of pollen from anther to stigma Fertilization Sperm nucleus fuses with egg to form zygote Fruit Formation Ovary matures into a fruit Seed Development Zygote develops into an embryo within a seed
✓ Correct answer: C. Fruit Formation: Ovary matures into a fruit
Answer: Fruit Formation. After fertilization, the ovary of the flower matures into a fruit. This process encloses the seeds, giving rise to a fruit that aids in seed dispersal. Pollination, fertilization, and seed development are important steps in the reproductive cycle, but the ovary's transformation into fruit specifically denotes fruit formation.
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Theory