HESI A2 Biology Practice Test

Correct Answer: D

Rationale: The correct answer is D: Biomes. Biomes are large geographical areas characterized by specific climate, vegetation, and animal life. Tundra, savannas, grasslands, deserts, and rainforests are all examples of biomes. They are classified based on factors like temperature, precipitation, and flora/fauna. Biomasses (A) refer to the total mass of living organisms in a given area. Biospheres (B) are the regions of the Earth where life exists. Biodiversity (C) refers to the variety and variability of life forms in a specific habitat, not the specific types of habitats themselves.

Correct Answer: D

Rationale: The correct answer is D: 206. The human adult skeletal system consists of 206 bones. This number includes bones of the skull, spine, rib cage, and limbs. The other choices are incorrect because: A) 412 is too high for the number of bones in the human body, B) 103 is too low and doesn't account for all bones, and C) "Over 300" is vague and doesn't provide an accurate count of the total bones in the human skeletal system.

Correct Answer: B

Rationale: The correct answer is B: Troposphere, stratosphere, mesosphere, thermosphere, exosphere. Rationale: 1. Troposphere: Closest to the Earth's surface where weather occurs. 2. Stratosphere: Contains the ozone layer, which absorbs UV radiation. 3. Mesosphere: Middle layer where meteors burn up. 4. Thermosphere: Upper layer with high temperatures and auroras. 5. Exosphere: Outermost layer where atmosphere transitions to space. Summary: A: Incorrect order, starts with exosphere which is the outermost layer. C: Incorrect order, mesosphere is placed before troposphere. D: Incorrect order, thermosphere comes before troposphere.

Correct Answer: B

Rationale: The correct answer is B: Create energy. Mitochondria are known as the powerhouse of the cell because they produce ATP, the primary energy source for cellular functions. They do this through a process called cellular respiration. Option A is incorrect as the nucleus controls the cell. Option C is incorrect as protein synthesis occurs in the ribosomes. Option D is incorrect as waste packaging is typically done by lysosomes.

Correct Answer: A

Rationale: Epithelial tissue is primarily found lining the organs, such as the skin, digestive tract, and respiratory tract. This tissue serves as a protective barrier and aids in absorption and secretion. The other choices, heart muscle, tendons, and spinal cord, are not locations where epithelial tissue is typically found. Heart muscle is cardiac muscle tissue, tendons are composed of dense regular connective tissue, and the spinal cord consists of nervous tissue. Therefore, the correct answer is A, organ lining, as it aligns with the typical locations of epithelial tissue in the body.