Are chemical
substances necessary for an
organism to be healthy and
survive.
A. Resources
B. Nutrients
C. Energy

It is nutrients. They enable organisms to survive and it makes them healthy.

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.

: -)

several tissues working together form an organ, and several organs together make up an organisms.

the group of cell that carries out special jobs are tissue.