Individual amino acids may be linked together, one after another, like the wagons of a train. What is the chemical bond that is used to attach on amino acid to the next?

try using substitution:

x + y - 6 = x - y. (i'm not giving you the exact answer). since 0 = x - y, then sub 0 in the equation with x - y. combine your like terms, and then use inverse operations, and you'll have your answer.

: -)

that scientist would be robert hooke

what in the weirdo : o

the answer is d p: cell, q: organ, r: organ system, s: tissue