The is a source of stem cells that has the characteristics of self-renewal and limited differentiation.

Amniotic fluid

Explanation:

Amniotic fluid found in the uterus is capable of forming different types of cells thus said to be self-renewal. However the cells have limited differentiation but when grown in conducive conditions in the lab, the cells can form different tissues like bones, liver, muscle cells and brain.

The amniotic fluid suspends the foetus allowing it to grow and move freely. It also protects the foetus from damage by any pressures acting on the mother's womb.

a. decomposes use carbon from dead organisms as fuel for cellular respiration, returning carbon dioxide back into the atmosphere.