TEAS Test 7 science

Correct Answer: B

Rationale: In a negative feedback loop, high levels of a hormone will inhibit the release of the hormone or its production. This mechanism is crucial for maintaining homeostasis by preventing excessive levels of hormones in the body. When a hormone reaches a certain concentration, it triggers the body to decrease its production or release, thereby ensuring a balance within the system. Choice A is incorrect because a negative feedback loop aims to counteract high hormone levels, not further stimulate them. Choice C is incorrect as high hormone levels do have an effect by triggering the feedback loop. Choice D is incorrect as the negative feedback loop operates within the same hormone system rather than increasing the need for an entirely different hormone.

Correct Answer: B

Rationale: The correct answer is B: 'The binding energy released during the fusion of light nuclei.' Nuclear fusion involves the combination of light nuclei to form a heavier nucleus, releasing energy in the process. This energy arises from the binding energy that keeps the nucleus intact. As lighter nuclei fuse, they create a more stable nucleus, and the excess energy is emitted as radiation. This fundamental process is the primary source of energy in stars and holds promise as a potential future energy source on Earth. Choices A, C, and D are incorrect. Choice A, 'The fission of heavy nuclei,' is related to nuclear fission, not fusion. Choice C, 'Electronic transitions within atoms,' refers to energy release in atomic transitions, not nuclear fusion. Choice D, 'Matter-antimatter annihilation,' is a process where matter and antimatter collide, converting their mass into energy, but it is not the energy source for nuclear fusion.

Correct Answer: C

Rationale: The bones of the skull are classified as flat bones. Flat bones are thin, flattened, and usually curved bones that provide protection to underlying organs and have a large surface area for muscle attachment. The skull bones fit this description as they protect the brain and have a broad surface for muscle attachment. Choice A (Long bones), B (Short bones), and D (Irregular bones) are incorrect classifications. Long bones are typically found in the extremities like the arms and legs, short bones are cube-shaped like the wrist and ankle bones, and irregular bones have complex shapes like the vertebrae. These classifications do not describe the bones of the skull, which are predominantly flat bones.

Correct Answer: D

Rationale: A) Cell wall: This is a structure found in plant cells that provides support and protection. B) Plasma membrane: Also known as the cell membrane, it surrounds the cell and regulates the passage of substances in and out of the cell. C) Vacuole: This is a storage organelle found in plant cells that stores water, nutrients, and waste products. D) Mitochondria: Mitochondria are membrane-bound organelles found in both plant and animal cells. They are responsible for producing energy in the form of ATP through cellular respiration. Therefore, the correct answer is D) Mitochondria, as it is a part of a plant cell.

Correct Answer: C

Rationale: The main function of the heart is to pump blood throughout the body. The heart acts as a muscular pump that circulates blood, delivering oxygen and nutrients to the body's tissues and removing waste products. Option A is incorrect because blood filtration is a function of the kidneys, not the heart. Option B is incorrect as gas exchange occurs in the lungs, not the heart. Option D is also incorrect as hormone production is mainly carried out by endocrine glands, not the heart.