Were the first cells autotrophs or heterotrophs?

The first cells were Autotrophs

Explanation:

Autotrophs are living organisms that are capable of producing their own food from simple inorganic molecules like atmospheric carbon dioxide and water in the presence of sunlight. In essence, they are capable of living on their own. A good example is green plants

On the other hand, heterotrophs are living organisms that rely on the food produced by autotrophs, thus, they are not the first cells to live. A good example is humans

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: