HESI A2 Biology 2024

Correct Answer: D

Rationale: The correct answer is D: Cocci. Cocci are spherical bacteria, typically found in clusters or chains. Clostridia (A) are rod-shaped bacteria, Bacilli (B) are also rod-shaped, and Spirilla (C) are spiral-shaped. The key characteristic of cocci is their round shape, distinguishing them from the other options.

Correct Answer: D

Rationale: The correct answer is D (2 females : 1 male) because in this scenario, the male offspring will inherit the X chromosome without the hemophilia gene from the mother. The female offspring will inherit one X chromosome with the hemophilia gene from the carrier mother and one X chromosome without the gene from the father. Therefore, 2 out of 3 offspring are predicted neither to carry nor manifest the disease. Choice A (0 females : 1 male) is incorrect because females can also be carriers of hemophilia. Choice B (1 female : 1 male) is incorrect because it doesn't account for the possibility of female carriers. Choice C (1 female : 0 males) is incorrect because it doesn't consider the transmission of the X chromosome from the mother to the sons.

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.

Correct Answer: D

Rationale: The correct answer is D: Mitosis. In the tip of a plant's root, cells undergo mitosis to increase in number. In mitosis, a parent cell divides into two identical daughter cells, ensuring the growth and repair of tissues. Meiosis, choice A, is a process of cell division that produces gametes with half the genetic material. Cytokinesis, choice B, is the process of cytoplasmic division following cell division. Fractioning, choice C, is not a biological process related to cell division. Mitosis is the only process mentioned that specifically describes cell division for growth and repair in plants.

Correct Answer: A

Rationale: The correct order of taxonomic categories from least to most specific is Kingdom, Phylum, Class, Order. This is because taxonomy categorizes organisms based on their shared characteristics, starting from broader groups to more specific ones. Kingdom is the broadest category, followed by phylum, which further narrows down the classification. Class is more specific than phylum, and order is the next level of specificity after class. Therefore, the correct answer is A: Kingdom, phylum, class, order. Choices B, C, and D are incorrect because they do not follow the hierarchical structure of taxonomy. Choice B has the order and class positions switched, choice C has the order and phylum positions switched, and choice D has the class and order positions switched. These alternative choices do not adhere to the principles of taxonomy where classification moves from broader to more specific categories.