ati teas 7 science

Correct Answer: C

Rationale: The correct answer is C: Phagocytes. Phagocytes are white blood cells responsible for the initial attack on pathogens by engulfing and digesting them. They include neutrophils, monocytes, and macrophages. Red blood cells (A) are not involved in the immune response. Platelets (B) are responsible for blood clotting, not attacking pathogens. Lymphocytes (D) play a role in specific immune responses but are not the primary cells responsible for the initial attack on pathogens.

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: Perpendicular to the direction of wave travel. In a transverse wave, particles of the medium move up and down (or side to side) perpendicular to the direction of wave travel. This motion creates crests and troughs in the wave. This motion is what characterizes a transverse wave, where the disturbance is perpendicular to the direction of energy transfer. Choices B, C, and D are incorrect because in a transverse wave, the particles do not move parallel to the direction of wave travel (B), in a circular motion (C), or opposite to the direction of wave travel (D).

Correct Answer: A

Rationale: The correct answer is A: Pulmonary vein. The pulmonary vein is the only blood vessel among the choices that carries oxygenated blood from the lungs back to the heart. The pulmonary artery (B) carries deoxygenated blood from the heart to the lungs. The aorta (C) carries oxygenated blood from the heart to the rest of the body. The vena cava (D) carries deoxygenated blood from the body back to the heart. Therefore, the pulmonary vein is the only blood vessel in the list that fits the description of carrying oxygenated blood from the lungs to the heart.

Correct Answer: C

Rationale: The correct answer is C, the Combined oral contraceptive pill. This method uses hormones like estrogen and progestin to prevent ovulation. Firstly, estrogen suppresses follicle-stimulating hormone (FSH) production, inhibiting follicular development. Secondly, progestin thickens cervical mucus, preventing sperm penetration. Lastly, progestin also inhibits luteinizing hormone (LH) surge, preventing ovulation. Spermicide (A) works by killing sperm but does not prevent ovulation. Barrier methods (B) like condoms and diaphragms physically block sperm from reaching the egg but do not affect ovulation. Intrauterine devices (IUDs) (D) work by preventing sperm from fertilizing the egg or by altering the uterine lining, but they do not directly prevent ovulation.