ATI TEAS 7 Science

Correct Answer: A

Rationale: The primary function of the digestive system is to break down food into nutrients for absorption by the body. This process involves mechanical and chemical digestion to convert food into molecules that can be absorbed by the intestines. Option A is correct as it describes this essential function. Option B is incorrect because the absorption of oxygen primarily occurs in the respiratory system. Option C is incorrect as the production of energy is mainly attributed to the metabolic processes within cells. Option D is incorrect as the regulation of body temperature is primarily controlled by the thermoregulatory system, not the digestive system.

Correct Answer: D

Rationale: The correct answer is D because water's unique polarity allows it to dissolve a wide range of substances. Water's polar covalent bonds enable it to form hydrogen bonds with other molecules, facilitating dissolution. Water's ability to dissolve various substances is crucial for biological processes such as nutrient absorption and waste removal. Choice A is incorrect because water is neutral in terms of its pH, not inherently having a neutral pH. Choice B is incorrect because water actually has a high specific heat capacity, which is why it can absorb and release large amounts of heat without significant temperature changes. Choice C is incorrect because while water does have polar covalent bonds, this property alone does not fully characterize water as much as its dissolving capabilities do.

Correct Answer: C

Rationale: The correct answer is C: Light energy from the sun. This is because photosynthesis, the process by which plants and other organisms convert light energy into chemical energy, is the primary source of energy in most ecosystems. Sunlight is essential for plants to produce food, which then sustains the entire food chain. Choice A (Chemical energy stored in bonds) is incorrect because this energy is a product of photosynthesis and not the primary source entering ecosystems. Choice B (Thermal energy from the Earth's core) is incorrect as it is not a significant source of energy for most ecosystems. Choice D (Kinetic energy from wind and water) is also incorrect as it is not the primary source of energy entering ecosystems, although it can play a role in some ecosystems.

Correct Answer: B

Rationale: Platelets are responsible for blood clotting, which is crucial for preventing excessive bleeding when a blood vessel is injured. They adhere to the site of injury and form a plug to stop bleeding. This function is essential for maintaining hemostasis in the body. Platelets do not carry oxygen like red blood cells (Choice A), fight infection like white blood cells (Choice C), or transport nutrients like plasma (Choice D).

Correct Answer: A

Rationale: The correct answer is A: Desertification. Desertification refers to the gradual loss of topsoil due to wind or water erosion, leading to the conversion of fertile land into desert-like conditions. This process is a result of unsustainable land use practices, such as overgrazing and deforestation. Leaching (B) is the process of nutrients being washed out of the soil by excess water, not specifically related to topsoil loss. Salinization (C) is the accumulation of salt in the soil, not directly related to topsoil erosion. Acidification (D) refers to the decrease in soil pH levels, not the loss of topsoil.