ati teas 7 science

Correct Answer: D

Rationale: The correct answer is D because chromosomal nondisjunction can lead to various genetic disorders such as Down syndrome (A), caused by an extra chromosome 21. Nondisjunction can also result in Turner syndrome (B) in females due to the absence of one X chromosome, and Klinefelter syndrome (C) in males with one or more extra X chromosomes. Therefore, all the options are potential consequences of chromosomal nondisjunction.

Correct Answer: B

Rationale: The correct answer is B: Alveoli. Alveoli are tiny air sacs in the lungs where gas exchange occurs between the air in the lungs and the blood. Oxygen from the air enters the blood, and carbon dioxide from the blood exits into the air. Trachea (A) is the windpipe that carries air to and from the lungs. Bronchi (C) are the main airways that branch off from the trachea. Diaphragm (D) is a muscle that helps with breathing by expanding and contracting the lungs, but it is not directly involved in gas exchange.

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: A

Rationale: The correct answer is A: Axon. The axon is responsible for transmitting signals away from the cell body towards other neurons or muscles. It is a long, slender projection of the neuron that carries electrical impulses known as action potentials. The axon is covered by the myelin sheath, which helps to speed up the transmission of signals. Summary: - B: Dendrite receives signals from other neurons and transmits them towards the cell body. - C: Synapse is the gap between neurons where neurotransmitters are released to communicate signals. - D: Myelin sheath insulates and speeds up signal transmission along the axon, but it is not responsible for transmitting signals itself.

Correct Answer: B

Rationale: The correct answer is B: 23. In humans, each normal cell contains 23 pairs of chromosomes, making a total of 46 chromosomes. The pairs consist of one chromosome from each parent, ensuring genetic diversity. Choices A, C, and D are incorrect because they do not reflect the accurate number of chromosome pairs in a human cell. Option A (46) is the total number of chromosomes, not pairs. Option C (64) and D (32) are not the correct numbers of chromosome pairs in a human cell.