What is the difference between DNA and RNA?

Correct Answer: B

Rationale: The correct answer is B. DNA has one less oxygen atom in its sugar molecule (deoxyribose) compared to RNA, which has a ribose sugar. Choice A is incorrect because RNA does not have an extra phosphate group. Choice C is incorrect as RNA actually has one more oxygen atom than DNA. Choice D is incorrect as DNA and RNA have different sugar molecules, with DNA having deoxyribose and RNA having ribose.

Correct Answer: B

Rationale: The correct answer is B, Mendel. Gregor Mendel is known as the father of genetics for his groundbreaking work with pea plants. He discovered the basic principles of heredity through his experiments, establishing the foundation of modern genetics. Choice A, Curie, is incorrect as Marie Curie was a physicist and chemist known for her pioneering research on radioactivity. Choice C, Hawking, is incorrect as Stephen Hawking was a theoretical physicist known for his work on black holes and cosmology. Choice D, Galileo, is incorrect as Galileo Galilei was an astronomer and physicist renowned for his contributions to the scientific revolution, particularly in astronomy.

Correct Answer: B

Rationale: Pleiotropy is best defined as one gene influencing multiple, seemingly unrelated phenotypic traits. This phenomenon showcases the multifunctionality of genes, where a single gene can have effects on various aspects of an organism's phenotype. Choices A, C, and D do not accurately capture the concept of pleiotropy. Option A refers to gene expression, not pleiotropy. Option C describes genetic interactions but not in the context of pleiotropy. Option D talks about missing genes, which is unrelated to the definition of pleiotropy.

Correct Answer: A

Rationale: The most important function of carbohydrates is to store and provide energy for the body through metabolic processes. Carbohydrates are broken down into glucose, which is used as the primary source of energy for various cellular functions. Choice B is incorrect because amino acids are the building blocks of proteins, not directly created by carbohydrates. Choice C is incorrect as the regulation of body temperature is primarily controlled by mechanisms such as sweating and shivering, not carbohydrates. Choice D is incorrect as insulation of body organs against shock is mainly provided by adipose tissue, not carbohydrates.

Correct Answer: A

Rationale: The correct answer is A, Meiosis. Meiosis is the cell division process that reduces the chromosome number from diploid to haploid, which is essential for sexual reproduction. Choice B, Photosynthesis, is the process by which green plants and some other organisms use sunlight to synthesize foods with the help of chlorophyll. Choice C, Mitosis, is a cell division process that results in two diploid daughter cells with the same number of chromosomes as the parent cell. Choice D, Cytokinesis, is the division of the cytoplasm following cell division.