ATI TEAS 7 Science

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: B

Rationale: The adrenal glands are responsible for secreting adrenaline and cortisol in response to stress, triggering the fight-or-flight response. Adrenaline increases heart rate and blood flow, while cortisol releases energy stores. The pancreas regulates blood sugar, the thyroid gland controls metabolism, and the pituitary gland regulates hormone production but are not directly involved in the fight-or-flight response.

Correct Answer: B

Rationale: The correct answer is B: Bacteria. Dysentery is primarily caused by pathogenic bacteria such as Shigella or Escherichia coli. Bacteria are single-celled microorganisms that can infect the intestines and cause symptoms like bloody diarrhea and abdominal pain. Helminths are parasitic worms that typically cause different types of infections. Protozoa are single-celled organisms that can also cause intestinal infections, but they are not the primary cause of dysentery. Fungi do not typically cause dysentery; they are more commonly associated with skin infections or respiratory issues. In summary, the correct answer is B because dysentery is most commonly caused by bacterial infections in the intestines.

Correct Answer: B

Rationale: The correct answer is B. A decomposition reaction involves a single compound breaking down into two or more simpler substances. In choice B, CaCO3 decomposes into CaO and CO2. This reaction follows the general form AB → A + B, making it a clear example of a decomposition reaction. Choices A, C, and D involve synthesis or combination reactions, where simpler substances combine to form a more complex compound, making them incorrect for this question.

Correct Answer: A

Rationale: The correct answer is A: Penicillins. Penicillins target the cell wall of bacteria by inhibiting the synthesis of peptidoglycan, a crucial component of the bacterial cell wall. This disrupts the integrity of the cell wall, leading to bacterial cell lysis. Tetracyclines (B), Macrolides (C), and Fluoroquinolones (D) target different bacterial components like protein synthesis or DNA replication, making them incorrect choices for this question.