AP BIOLOGY

Detailed explanation-1: -All organisms including ourselves, start life as a single cell called zygote.

Detailed explanation-2: -This single cell divides to form more cells and group up to perform specialised functions. In this way, multicellular organisms like an ant, an elephant or a plant are formed.

Detailed explanation-3: -Embryos are really fascinating because they start off as a single cell. And then at some point, the embryo starts to generate organs, tissue, skin, the brain, and muscle.

Detailed explanation-4: -A multicellular organism develops from a single cell (the zygote) into a collection of many different cell types, organized into tissues and organs. Development involves cell division, body axis formation, tissue and organ development, and cell differentiation (gaining a final cell type identity).

Detailed explanation-5: -The first known single-celled organisms appeared on Earth about 3.5 billion years ago, roughly a billion years after Earth formed.