ati teas 7 science

Correct Answer: C

Rationale: The correct answer is C: Nucleus. The nucleus is responsible for controlling the activities of the cell because it houses the cell's DNA, which contains instructions for cellular functions. It regulates gene expression and controls the production of proteins. The Golgi apparatus (choice A) is involved in processing and packaging proteins. Mitochondria (choice B) are responsible for energy production. Ribosomes (choice D) are responsible for protein synthesis. However, the nucleus is the main organelle that directly regulates and controls the activities of the cell.

Correct Answer: A

Rationale: The correct answer is A: Neuron. Neurons are specialized cells that transmit electrical impulses in the nervous system. They consist of a cell body, dendrites to receive signals, an axon to transmit signals, and synaptic terminals to communicate with other neurons. The axon is the long fiber that carries the electrical impulses away from the cell body. Myelin is a fatty substance that insulates and speeds up signal transmission along the axon. Dendrites receive signals from other neurons and transmit them towards the cell body. Therefore, the neuron is the fundamental structure responsible for transmitting electrical impulses, making it the correct answer.

Correct Answer: C

Rationale: The correct answer is C: Peripheral nervous system. This system consists of nerves that connect the sensory organs (such as eyes, ears, skin) to the central nervous system (brain and spinal cord). It transmits sensory information from these organs to the CNS for processing. The autonomic nervous system (A) controls involuntary functions, somatic nervous system (B) controls voluntary movements, and central nervous system (D) processes and integrates information but does not directly transmit signals from sensory organs.

Correct Answer: C

Rationale: The correct answer is C: RBC (Red Blood Cell). RBCs are biconcave discs that are round and flat without a nucleus. This unique shape allows for efficient gas exchange and flexibility to pass through narrow capillaries. Rationale: 1. Plasma (Choice A) is the liquid component of blood that carries various substances but does not have a specific shape or structure like RBCs. 2. Platelets (Choice B) are cell fragments involved in blood clotting and do not have the described characteristics of a biconcave disc without a nucleus. 3. WBCs (Choice D) are white blood cells responsible for immune responses and have a nucleus, unlike RBCs. In summary, RBCs are the only blood constituent among the choices that fits the description provided in the question.

Correct Answer: C

Rationale: The correct answer is C: Change in color. Chemical reactions involve the formation of new substances, which is a key characteristic. Energy is either released or absorbed during a chemical reaction, leading to changes in temperature. However, changes in color are not always indicative of a chemical reaction as it can be influenced by factors like impurities or physical changes. Therefore, C is not a reliable characteristic of a chemical reaction compared to the other choices.