Practice TEAS Science Test

Correct Answer: B

Rationale: The correct answer is B: Sebaceous gland. Sebaceous glands produce sebum, an oily substance that helps moisturize the skin and hair. The sudoriferous gland produces sweat, not oil. The hair follicle anchors the hair to the skin, it does not produce oil. Melanocytes are responsible for producing melanin, the pigment that gives skin its color, not oil. Therefore, the sebaceous gland is the structure responsible for producing oil to keep the skin and hair moisturized.

Correct Answer: B

Rationale: The correct answer is B: 12 NADPH and 18 ATP. In the Calvin cycle of photosynthesis, each molecule of CO2 requires 2 NADPH and 3 ATP for reduction to glucose. Therefore, to reduce 6 molecules of CO2, you would need 6 x 2 = 12 NADPH and 6 x 3 = 18 ATP. This is why choice B is the correct answer. Choices A, C, and D have incorrect combinations of NADPH and ATP that do not match the stoichiometry of the Calvin cycle for the reduction of CO2 to glucose.

Correct Answer: B

Rationale: The correct answer is B: Laryngopharynx. The laryngopharynx is part of the pharynx where both the respiratory and digestive systems intersect. It serves as a common passageway for both food and air. When we swallow, the epiglottis covers the larynx to prevent food from entering the trachea. A: The esophagus is solely a passageway for food from the mouth to the stomach. C: The nasopharynx is a part of the upper respiratory tract and not involved in the passage of food. D: The trachea is strictly a passageway for air to enter and exit the lungs.

Correct Answer: A

Rationale: The correct answer is A: Ectoderm. During embryonic development, the nervous system originates from the ectoderm layer. The neural plate forms from the ectoderm, which further develops into the neural tube and neural crest cells, giving rise to the brain, spinal cord, and peripheral nervous system. The other choices, B: Endoderm, C: Gastroderm, and D: Mesoderm, do not give rise to the nervous system. Endoderm forms the innermost layer of organs like the gut, Gastroderm is not a recognized germ layer, and Mesoderm gives rise to structures like muscles, bones, and connective tissues, not the nervous system.

Correct Answer: C

Rationale: The correct answer is C: Nucleus. The nucleus contains the cell's genetic material in the form of DNA, which carries the instructions for the cell's functions and characteristics. This is where processes such as transcription and replication occur. Ribosomes (choice A) are responsible for protein synthesis. Mitochondria (choice B) are the powerhouse of the cell, producing energy. Cytoplasm (choice D) is the fluid that fills the cell and supports organelles, but it does not store genetic information.