Two frog popalations of the same species, living in two neighboring lakes sing slightly different courtship songs. Assume that coutship song differences have a genetis basis and that no fitness differences are linked to the song types, Now predict what likely happens to the songs used by the two frog populations after increased irrigation makes the land between the two lakes wetter which leads to increasesd connectedness between the lakes "nd hence the possibility of more frequent mating-mong the populations A. No change in the frog courtship songs of the two lakes. B. The songs become more similar to each other C. The songs become more different from each ether D. Female preferences will change to prefer higher frequency frog calls E. None of the above

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).

Has magnification ability of hundreds of thousands of times

Question 17 (1 point) where does penicillin come from? a. it is a chemical that man invented b. it is a fungus c. it is a toxin made by other bacteria d. it was discovered in archaebacteria