Muscles are only able to actively contract, and thus to pull. To produce a movement...

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Muscles are only able to actively contract, and thus to pull. To produce a movement in one direction (for example, flex your arm) you activate one set of muscles, and to produce a movement in the opposite direction (for example, extend your arm) you activate another set of muscles.This is muscle organization is an example of which type of control?
a) agonistic
b) antagonistic   opposite responses?
c) synergistic
d) tonic

What are some examples of molecules that would not need a receptor in/on the extracellular surface of cells? Choose any that apply.
a) small, gaseous molecules b/c nonpolar
b) nonpolar molecules
c) polar molecules
d) lipophilic molecules b/c nonpolar
e) lipophobic molecules