ati teas 7 science

Correct Answer: B

Rationale: The correct answer is B. A decomposition reaction involves a single compound breaking down into two or more simpler substances. In choice B, CaCO3 decomposes into CaO and CO2. This reaction follows the general form AB → A + B, making it a clear example of a decomposition reaction. Choices A, C, and D involve synthesis or combination reactions, where simpler substances combine to form a more complex compound, making them incorrect for this question.

Correct Answer: A

Rationale: The correct arrangement of the small intestine segments is Duodenum, Jejunum, Ileum. The duodenum is the first segment where digestion occurs. The jejunum is the middle segment responsible for absorption, followed by the ileum for further absorption and passage of undigested material to the large intestine. Option A is correct as it follows the natural anatomical order and functional progression of the small intestine segments. Options B and C are incorrect as they incorrectly order the segments. Option D is also incorrect as there is a correct arrangement.

Correct Answer: B

Rationale: The correct answer is B: Cerebrospinal fluid. This is the protective fluid that surrounds the brain and spinal cord. It acts as a cushion, providing mechanical protection, and helps to maintain a stable environment for the central nervous system. Blood (A) does not directly surround the brain and spinal cord. Myelin sheath (C) is a protective covering of nerve fibers, not the fluid surrounding the brain and spinal cord. Insulin (D) is a hormone involved in regulating blood sugar levels and is not the fluid that protects the brain and spinal cord.

Correct Answer: B

Rationale: The correct answer is B: Mitosis. Mitosis is the type of cell division responsible for growth and repair in multicellular organisms. During mitosis, a cell divides into two identical daughter cells, ensuring the growth and repair of tissues. Meiosis (A) is involved in sexual reproduction, not growth or repair. Binary fission (C) is a form of asexual reproduction in prokaryotic cells, not growth or repair. Osmosis (D) is the passive movement of water across a semi-permeable membrane, not a form of cell division.

Correct Answer: B

Rationale: The correct answer is B: In a covalent bond, the shared electrons spend more time closer to the more electronegative atom. This is because the more electronegative atom attracts the electrons more strongly, causing them to be closer to that atom. This creates a partial negative charge on the more electronegative atom and a partial positive charge on the other atom. This distribution of electron density contributes to the stability of the covalent bond. Choices A, C, and D are incorrect because: A: Are completely transferred to one atom - This describes an ionic bond, not a covalent bond. C: Remain equidistant between the two atoms - Shared electrons in a covalent bond are not equidistant but are closer to one atom. D: Do not influence the bond strength - The distribution of shared electrons significantly influences the strength and properties of a covalent bond.