9. A student compares a model of a fatty acid to a model of an amino acid. Which statement accurately compares two models?
a. Both models contain the same elements
b. Both models are polymers that each contain different monomers
c. The two models obtain elements, but the amino acid contains more types of
elements
d. The two models are structurally identical, but they are using different elements.

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.

: -)

i believe it would be c: tons.

b is the answer and if you need further with anything message me

the oldest known insects are believed to live around 400 millions ago as suggested by the fossil records.   some plants having woody stems also evolved during this time.

after the evolution of insects the first four legged species or the tetrapods evolved in shallow freshwater habitats from the intermediate species approximately 397 million years ago. the tetrapods went on conquering the land giving rise to amphibians, reptiles, mammals and birds.

the major split in tetrapods first occurred 340 million years ago branching off from amphibians.

363 million years ago when the carboniferous period began the insects started roaming on land and taking flights, following which the four limbed tetrapods adapted in the terrestrial habitat.