Answer:
They use a hard shell, but not hard enough though because we humans can get through them hehehe
What do Enzymes enable cell reactions to do? proceed at normal temperature, lowers the activation energy needed for reactions to being. ... normal active energy is too high so this allows the reactions to occur at body temp.
It depends on the organism, they all vary, they can reach up to 90% but I’m not sure so pick C:70%