Question

What is the experimental evidence that cells are the smallest unit of life.

Answer 1

A cell can be termed as cytoplasm surrounded by a cellular membrane. Cells are known as the smallest unit of life, based on the fact that the features of a living organism can also be performed by an individual cell. The basic signs of life are 1)response to external and internal stimuli 2) reproduction 3) utilization of energy 4) growth. A cell can perform these basic signs of life by itself.  

When separated from an organism, cells can continue to live on, produce new cells, utilize energy when they are kept in favourable environments. Also, many prokaryotic cells such as bacteria, archaea and many unicellular eukaryotic organisms such as Amoeba, Paramecium are capable of performing the basic signs of life.

Therefore, we can conclude that cells are the smallest units which are capable of living independently. Hence, cells are the smallest units of life.