Gram positive . have a thick capsule that traps the crystal violet stain. b. have a second, outer membrane that retain the crystal violet stain. c. have a periplasmic space that traps the crystal violet. d. have multiple layers of peptidoglycan that retain the crystal violet stain.

Study the picture of the ocean. which is the best example of an organism’s niche shown in the picture? a. the environment contains several of the same species of coral. b. the shallow area of the ocean meets the needs of the coral and the fish. c. the ocean has fish and coral that live in the same area. d. the coral take in food from the water and provide shelter for the fish.

18. over time, how do sand dunes tend to migrate? a. perpendicular to the movement of the wind b. in the same direction as the wind blows c. toward the wind d. in random directions

Choose the incorrect statement (a) the motor end plate membrane is only capable of generating graded potentials, but it is contiguous with the skeletal muscle sarcolemma, which can generate action potentials. (b) propagation of an action potential through the t-tubules into the sarcoplasmic reticulum triggers the release of ca++ into the cytoplasm of a skeletal muscle fiber. (c) the generation of suprathreshold endplate potentials in multiple muscle fibers could be due to the increased frequency of action potential generation at the axon hillock of a single motor neuron. (d) a greater amount of ach would be found in the presynaptic vesicles of a motor unit that fired several action potentials after exposure to botulinum toxin, than in a motor unit that fired several action potentials after exposure to the venom of the krait snake (which contains α-bungarotoxin).