The four main types of tissues of animals are: muscular, which is in _; nervous, which is in _; epithelial, which is in _; the connective, which is in _.

the skin; cartilage; the brain; the heart

cartilage; the skin; the heart; the brain

the brain; the heart; cartilage; the skin

the heart; the brain; the skin; cartilage

Which type of organism is missing from the food web seen in the illustration? primary consumers decomposers primary producers secondary consumers

Long term exposure to waves can cause sunburns and skin cancer.

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).