ati teas 7 science

Correct Answer: A

Rationale: The correct answer is A: Iron (Fe). This is because an element with atomic number 26 corresponds to Iron on the periodic table. The mass number of 56 indicates the total number of protons and neutrons in the nucleus of the atom, which is consistent with the atomic mass of Iron. Choice B, Cobalt, has an atomic number of 27, not 26. Choice C, Nickel, has an atomic number of 28, not 26. Choice D, Manganese, has an atomic number of 25, not 26. Therefore, based on the given atomic number and mass number, Iron is the most likely element.

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.

Correct Answer: C

Rationale: The myelin sheath is derived from nervous tissue, specifically glial cells. Glial cells, also known as neuroglia, support and protect nerve cells. They produce the myelin sheath, which insulates nerve fibers and allows for faster transmission of nerve impulses. Epithelial tissue (choice A) primarily covers and lines body surfaces, muscle tissue (choice B) is responsible for movement, and connective tissue (choice D) provides support and structure to the body. None of these tissues are involved in the production of the myelin sheath, making them incorrect choices.

Correct Answer: B

Rationale: The correct answer is B. Sunscreen protects the skin by absorbing UV rays and converting them to heat. This process prevents the UV rays from penetrating the skin and causing damage. Reflecting UV rays (A) would not be as effective as absorbing them. Blocking UV rays completely (C) is not possible with sunscreen. Stimulating melanin production (D) is not the main mechanism of how sunscreen works to protect the skin.

Correct Answer: B

Rationale: The correct answer is B: Insulin. Insulin is responsible for regulating blood sugar levels by facilitating the uptake of glucose into cells for energy production and storage. It helps lower blood sugar levels by promoting glucose utilization. Thyroxine (A) regulates metabolism, adrenaline (C) is involved in the fight-or-flight response, and cortisol (D) regulates stress response and metabolism, but they do not directly regulate blood sugar levels like insulin does.