What would happen if a large organism was made of a single cell?

All single-celled organisms contain everything they

need to survive within their one cell. These cells are able to get

energy from complex molecules, to move, and to sense their

environment. ENERGY, it'd need massive amounts of energy to survive.

Organisms made of one cell do not

grow as large as organisms made of many cells. But all living things

need to get energy. All living things also need to obtain materials to

build new structures inside cells or replace worn-out cell parts.

As a  result, individual cells grow larger over time. It'd need lots of materials to keep growing.

Organisms respond to changes in the environment. Even microscopic

organisms respond to conditions such as light, temperature, and

touch. The ability to respond allows organisms to find food, avoid

being eaten, or perform other tasks necessary to survive.

For being so large and only a single celled it'd would probably only be found in a very safe environment.

i think the answer is composed of atoms