HESI A2 Biology 2024

Correct Answer: B

Rationale: The correct answer is B because it involves testing the hypothesis in a controlled manner. By dividing participants into two groups with similar average blood pressure, any observed changes can be more confidently attributed to the yoga practice. Testing each participant's blood pressure after participating in a yoga class allows for individual assessment and comparison within the groups. This design helps isolate the effect of yoga on reducing blood pressure by controlling for other variables. Option A lacks a control group for comparison, making it difficult to determine if the changes in blood pressure are solely due to yoga practice. Option C introduces an additional variable (watching television) in one group, which could confound the results. Option D introduces gender as a variable, which could also affect the results. By eliminating these potential confounding factors, option B provides a more valid and reliable test of the hypothesis.

Correct Answer: B

Rationale: The correct answer is B: Enzymes are made from proteins. Proteins are complex molecules made up of amino acids, which are the building blocks of enzymes. Enzymes are biological catalysts that speed up chemical reactions in living organisms. They have specific shapes that allow them to bind to substrates and facilitate reactions. Lipids (choice A) are not typically involved in enzyme structure. Double chains of DNA (choice C) refer to the structure of DNA, not enzymes. Enzymes themselves are catalysts (choice D) and do not bind with other catalysts.

Correct Answer: B

Rationale: The correct answer is B: Green. Chlorophyll, the pigment responsible for photosynthesis, absorbs light most efficiently in the red and blue regions of the spectrum. Green light is reflected, making it least effective. Violet, orange, and red lights are more readily absorbed by chlorophyll, enhancing photosynthesis. This is due to the specific absorption spectrum of chlorophyll, where green light is least absorbed.

Correct Answer: D

Rationale: The correct answer is D (46). Humans have 23 pairs of homologous chromosomes, totaling 46 chromosomes. Each pair consists of one chromosome from each parent. Choices A (13), B (23), and C (26) are incorrect as they do not represent the total number of pairs of homologous chromosomes in humans. A and C do not reflect the correct total number of chromosomes, while B only specifies the number of individual chromosomes, not pairs. Therefore, option D is the correct choice because it accurately represents the total number of homologous chromosome pairs in humans.

Correct Answer: D

Rationale: The correct answer is D: Fragmentation. Fragmentation is the form of asexual reproduction where an organism breaks into fragments, and each fragment can develop into a new individual. In this scenario, ocean waves tearing sponges into pieces allows each piece to grow into a new sponge, demonstrating fragmentation. A: Budding involves the formation of a new organism from a small outgrowth on the parent organism. This process does not involve breaking the parent organism into pieces. B: Vegetative propagation is a method of asexual reproduction in plants where new individuals are formed from vegetative parts like stems or roots. This does not apply to sponges. C: Binary fission is a form of reproduction seen in single-celled organisms where the cell divides into two identical cells. This process is not applicable to sponges, which are multicellular organisms.