The above experimental design description is an example of which of the following types of experiments?

Correct Answer: C

Rationale: The above experimental design description involves the manipulation of an independent variable (light exposure) to observe its effects on the dependent variable (plant growth) under controlled conditions. In a controlled experiment, researchers actively manipulate one or more variables while keeping all other variables constant to establish cause-and-effect relationships. Choice A, a field experiment, typically takes place in a real-world setting but still involves manipulation and control of variables. Choice B, a natural experiment, involves observing naturally occurring differences in variables without researcher intervention. Choice D, an observational study, does not involve manipulation of variables, making it different from the described experimental design.

Correct Answer: D

Rationale: The correct answer is cytotoxic T cells. Cytotoxic T cells are a type of white blood cell that is crucial in adaptive immunity. They are specialized in recognizing and destroying infected or abnormal cells in the body. Neutrophils are primarily involved in innate immunity, providing rapid response to infections. Antibodies are proteins produced by B cells and are essential in specific immune responses, but they do not directly attack pathogens. Memory B cells are part of the adaptive immune response, responsible for mounting a quicker and stronger response upon re-exposure to a pathogen. However, they do not directly seek out and destroy pathogens like cytotoxic T cells do.

Correct Answer: A

Rationale: Arteries are blood vessels that carry oxygen-rich blood away from the heart to various parts of the body. Therefore, they are the vessels that transport blood away from the heart. Veins, on the other hand, transport blood back to the heart. Capillaries are tiny blood vessels where the exchange of nutrients and waste products occurs between blood and tissues, not vessels that transport blood to the heart. Venules are small veins that collect blood from capillaries and connect them to larger veins, rather than transport blood to the heart.

Correct Answer: C

Rationale: The large intestine's primary function is to absorb water from undigested food remnants and compact them into solid waste (feces). This process helps regulate hydration levels in the body and aids in waste elimination. Choices A, B, and D are incorrect. Absorbing digested material into the blood is mainly done in the small intestine, nutrient processing and metabolizing occur in various parts of the digestive system, and bile production and storage are functions of the liver and gallbladder, not the large intestine.

Correct Answer: D

Rationale: The property of water that is responsible for its ability to dissolve important nutrients like ionic salt compounds is its high polarity. Water is a polar molecule with a positive and negative end, which allows it to attract and surround individual ions from salt compounds, causing them to dissociate and dissolve in water. This property makes water an excellent solvent for various substances necessary for life functions. Adhesion refers to the ability of water molecules to stick to other substances, cohesion is the attraction between water molecules themselves, and high specific heat is the amount of heat energy required to raise the temperature of water. While these properties are important characteristics of water, they are not directly responsible for its ability to dissolve ionic salt compounds.