ati teas 7 science

Correct Answer: A

Rationale: The correct answer is A: Neuron. Neurons are the fundamental unit of the nervous system because they are specialized cells that transmit information through electrical and chemical signals. Neurons have a unique structure with dendrites, cell body, and axon, allowing them to receive, process, and transmit signals. Nerves (B) are bundles of neurons, ganglia (C) are clusters of neuron cell bodies, and neuroglia (D) are support cells in the nervous system. Neurons are the primary functional unit responsible for communication in the nervous system.

Correct Answer: C

Rationale: Gold (C) is the correct answer because it is highly malleable and does not tarnish. Gold is a popular choice for jewelry due to its durability and resistance to corrosion. Iron (A) is not commonly used in jewelry due to its susceptibility to rust. Copper (B) is malleable but prone to tarnishing. Silver (D) is malleable but can tarnish over time, making it less ideal for long-lasting jewelry pieces.

Correct Answer: D

Rationale: The correct answer is D, both transcription and translation. First, DNA undergoes transcription to produce mRNA, which carries the genetic information. Then, during translation, mRNA is used by ribosomes to synthesize proteins. Replication (A) is the process of copying DNA, not directly related to protein synthesis. Transcription (B) is the step where DNA is transcribed into mRNA. Translation (C) is the process where mRNA is translated into proteins. Therefore, both transcription and translation are essential steps in the flow of genetic information from DNA to protein.

Correct Answer: B

Rationale: The correct answer is B: Alveoli. Alveoli are tiny air sacs in the lungs where the exchange of oxygen and carbon dioxide occurs during respiration. Oxygen from the air we breathe diffuses into the bloodstream, while carbon dioxide from the blood is released into the alveoli to be exhaled. The trachea (A) is a tube that carries air to and from the lungs, the bronchi (C) are branches of the trachea, and the diaphragm (D) is a muscle that helps with breathing but is not directly involved in gas exchange. Therefore, the alveoli are responsible for gas exchange in the respiratory system.

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.