PLEASE HELP!
After a fetus has developed for only three months, what is its skeleton made of?

Select the correct answer. which term do biologists use to describe the average number of individuals of a species per unit area? a. carrying capacity b. population density c. minimal viable population d. survivability curve

Is there any species that went extinct in recent years due to natural causes (not caused by human interaction). if so, what caused it?

What happens to the amount of waste in the pond as the ecosystem ages?