Have Scientific advances have led to decreased energy efficiency and waste reduction.

the element that provides strength to the exoskeletons of clams and oysters is phosphorus. this is so because calcium carbonate is the main component in the shells.

explanation:

option a and d is the correct answer

i hope this u

plz mark as the brainliest answer

the answer is: reproductively

i think i spelled it wrong lol

anyways hope i

-lavira: )

i think the answer is a.keratin is the pigment responsible for skin color.