which statement regarding energy content is true

HESI A2

Biology HESI A2 2024

1. Which statement regarding energy content is true?

A. Decomposers < secondary consumers
B. Primary consumers < producers
C. Producers > secondary consumers
D. Secondary consumers < primary consumers

Correct answer: C

Rationale: The correct answer is C: "Producers > secondary consumers." Producers, like plants, are the foundation of the energy pyramid, containing the highest energy content in an ecosystem. They convert solar energy into chemical energy through photosynthesis. Secondary consumers, being organisms that feed on other organisms, have lower energy content compared to producers. This hierarchy in energy content is due to the transfer of energy through trophic levels. Choice A is incorrect because decomposers, though essential for nutrient recycling, typically have lower energy content than secondary consumers. Choice B is incorrect because primary consumers, which feed directly on producers, have lower energy content than producers. Choice D is incorrect because secondary consumers have lower energy content compared to primary consumers.

2. How should a researcher test the hypothesis that a particular species of bird vocalizes most in the hours around dawn?

A. Observe a flock of the birds in captivity and record them at two-hour intervals from predawn until sunset for a month.
B. Observe a flock of the birds in the wild and record them at one-hour intervals from predawn until sunset in several seasons.
C. Observe a flock of the birds in the wild and record them in predawn and postdawn hours every day for six months.
D. Observe a flock of the birds in the wild, record them at one-hour intervals for a month, and compare that recording to recordings of other species.

Correct answer: C

Rationale: Observing a flock of the birds in the wild and recording them in predawn and postdawn hours every day for six months would be the best way to test the hypothesis that a particular species of bird vocalizes most in the hours around dawn. This method allows for consistent monitoring of the birds during specific times of interest over an extended period, providing a comprehensive dataset to accurately analyze the vocalization patterns. Options A and B do not focus specifically on dawn hours, making them less suitable for testing the hypothesis. Option D introduces a comparison with other species, which is unnecessary and distracts from the main objective of studying the vocalization pattern of the particular bird species around dawn.

3. Cells reproduce by different processes, all of which fall into what two categories?

A. Sexual reproduction and binary fission
B. Sexual reproduction and asexual reproduction
C. Asexual reproduction and binary fission
D. Asexual reproduction and mitosis

Correct answer: B

Rationale: Cells reproduce through two main processes: 'sexual reproduction and asexual reproduction.' Sexual reproduction involves the fusion of gametes to produce offspring with genetic variation, while asexual reproduction involves the production of offspring genetically identical to the parent. Choice A is incorrect because binary fission is a form of asexual reproduction, not sexual reproduction. Choice C is incorrect because it combines two forms of asexual reproduction. Choice D is incorrect because mitosis is a specific type of cell division, not a form of reproduction involving the production of offspring.

4. What is the role of ribosomes in the cell?

A. Break down cellular waste
B. Organize cellular division
C. Synthesize proteins
D. Provide cellular structure

Correct answer: C

Rationale: The correct answer is C: Synthesize proteins. Ribosomes are responsible for protein synthesis by linking amino acids together. Choice A is incorrect because ribosomes do not break down cellular waste. Choice B is incorrect as ribosomes do not organize cellular division. Choice D is incorrect because ribosomes do not provide cellular structure.

5. How do animal cells divide?

A. Through a contractile ring
B. Via a cell plate
C. Both methods
D. None of the above

Correct answer: A

Rationale: Animal cells divide through a contractile ring made of actin and myosin filaments. The ring contracts, pinching the cell membrane in the middle to form two daughter cells. Plant cells use a cell plate due to their rigid cell walls, making choices B and C incorrect. Choice D is incorrect as animal cells do use the contractile ring method for division.