Answer:
The correct answer is 4.ecosystem.
Explanation:
An ecosystem is a system, that is, a set of elements that interact with each other, in which such elements are: physical environment, living beings and their interactions (predator-prey, parasite-host, competition, symbiosis, pollination, distribution of seeds , etc.) The interrelation between living beings (competition, parasitism, etc.) occurs through cycles of matter and energy flows on which the functioning of the entire ecosystem depends.
Most adult stem cells come from the bone marrow.
<span>B. Marsupials. </span>Amniotic eggs is a unique kind of egg because they possess a semipermeable shell to protect the egg but it also allows gas exchange. Inside an amniotic egg contains the amnion, chorion and allantois. Animals that lay amniotic eggs are called amniotes, which include reptiles, birds, dinosaurs, monotremes (platypus).
I think its a hope that helped :)
A. objects made of crystals minerals water and air
Process of elimination-
there isn’t organic matter in rocks so D is out
they are made of minerals so B is out
some types of rock (pumice) have air bubbles in them so A is more likely than C
