D. Growth. Material forming cells or tissue like cytoplasm.
I believe it is azotemia.
Answer:
Mold fossil.
Explanation:
The clamshell shaped cavity is a mold fossil owing to the fact that the clamshell died, its body deteriorated but while it is deteriorating it is being covered by sediment. As a result when the clamshell completely disappears it will leave an impression on the sediment, in other words, it is a mold of the prehistoric clamshell.
