When contracted, ________ prevents movement of chyme from the stomach to the small intestine

In streams flowing through dense forest, ____; therefore nutrients from organic detritus is particularly important

a. dissolved oxygen levels are high b. dissolved oxygen are low c. the water moves slowly d. dense vegetation blocks light necessary for photosynthesis e. photosynthetic organisms make up most of the life in these streams

A nutritionist has an enclosed cabinet used to calculate the calories in foods. The protocol requires that the food is set on fire as fuel under a water tank and then the temperature change in the water is equated to the calorie content in the foods. High calorie foods burn better than low calorie foods. Why?

a. High calorie foods have less water than low calorie foods and water cools the heat transfer reaction during combustion. b. The third law of thermodynamics states that change of state reactions like combustion will result in decreased entropy. c. Burning the foods is an energy transformation. The second law of thermodynamics says that no energy transformation is 100% efficient. Some of the energy is usually lost to the surroundings as heat. d. The oxygen given off by high calorie foods is extremely combustible and that is what generates the heat. Foods that are burned have fewer calories after the protocol.

_________________ produces new species and _________________ takes them away.

A. Extinction; speciation B. Speciation; extinction C. Background extinction; mass extinction D. Gradual change; punctuated equilibrium

When an animal cell is placed in a hypotonic solution and water enters the cell via osmosis, the volume of the cell increases until it bursts. This does not happen to plant cells, because _____.

a. certain gated channel proteins embedded in their plasma membranes open as osmotic pressure decreases, allowing excess water to leave the cell b. they have cell walls, which prevent the entry of water by osmosis c. they have large central vacuoles, which provide abundant space for storage of incoming water d. they have cell walls, which provide pressure to counteract the pressure of the incoming water