Lichens with soil formation because they ( its a multi choice question )a)  are often the first organisms to enter barren environments. b)  plants get nutrients and water from soil. c)  increase the surface area of roots. d)  prevent rocks from eroding.

What element is able to combine with itself and hydrogen to form large molecules ?

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).

Which nutrients contain nitrogen in addition to carbon hydrogen, and oxygen? a) vitamins. b) proteins. c) carbohydrates. d) fat