ATI TEAS Science Practice Test

Correct Answer: B

Rationale: The correct answer is B. Progesterone, produced in the ovaries, stimulates uterine lining growth and plays a crucial role in regulating the menstrual cycle. Insulin is produced in the pancreas to regulate blood sugar levels, not in the ovaries. Adrenaline is produced by the adrenal glands and increases heart rate in response to stress or danger, not in the ovaries. Cortisol, also produced by the adrenal glands, helps regulate the body's response to stress, not in the ovaries.

Correct Answer: A

Rationale: The correct answer is A: White matter and grey matter. The spinal cord is composed of an exterior layer of white matter, which surrounds an interior core of grey matter. White matter consists mainly of myelinated axons, while grey matter contains cell bodies, dendrites, and unmyelinated axons. White matter is responsible for transmitting nerve signals up and down the spinal cord, while grey matter processes sensory information and initiates motor commands. The other choices (B, C, D) are incorrect as they do not represent the anatomical layers of the spinal cord. Epithelial and connective tissue, adipose and muscular tissue, dermis, and hypodermis are not the layers of the spinal cord but are found in other parts of the body such as skin and organs.

Correct Answer: B

Rationale: The endocrine system does not include a transportation network throughout the body. While the cardiovascular system transports blood, oxygen, and nutrients, the immune system has lymphatic vessels for immune cell transportation, and the nervous system transmits signals via neurons. In contrast, the endocrine system coordinates bodily functions by releasing hormones directly into the bloodstream, which then act on target organs or tissues. This delivery mechanism is different from the continuous transportation networks found in the other systems listed, making the endocrine system the correct choice for this question.

Correct Answer: D

Rationale: The correct answer is D. In the proliferative phase of the uterine cycle, the uterine lining thickens in preparation for a possible pregnancy. Ovulation occurs around day 14 of the cycle. The menstrual phase is when the uterine lining sheds if pregnancy has not occurred. Choice A is a duplicate of the correct answer. Choice B is incorrect as ovulation occurs during the mid-cycle, which is the ovulatory phase, not the secretory phase. Choice C is incorrect because the uterine lining sheds during the menstrual phase, not the secretory phase.

Correct Answer: C

Rationale: The correct answer is C: Double-stranded, helix. DNA is structured as a double helix formed by two strands of nucleotides. The nucleotides are paired with complementary bases (A-T and C-G) in the center, held together by hydrogen bonds. This double-stranded helical structure is a fundamental characteristic of DNA and essential for its function in storing genetic information. Choices A, B, and D are incorrect because DNA is not single-stranded; it consists of two strands that run antiparallel to each other and are connected via hydrogen bonds. Additionally, DNA does not have a linear structure but rather a helical one, providing stability and protection to the genetic information it carries.