A community is concerned that its river has become polluted. Analysis of water samples shows small amounts of over 20 different chemicals. Which of the following is the most likely cause for the increase in pollution?

The instructions for making proteins come originally from

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).

Select the correct answer. which statement applies only to the axial skeleton, not the appendicular skeleton? a. it contains a pivot joint. b. it has muscles attached that work in pairs. c. it contains red bone marrow. d. it possesses fossa for bone articulation. e. it protects the heart and lungs.