Question

What do the different scientific , theories about how life began on earth have in common?

Answer 1

All the theories about life on earth have a common point that living organisms are evolved from the non living, i.e., atoms (electron, proton, neutron)
Further from atoms - molecules - tissue - organs - organ system - organisms - population - community and so on the evolution goes on.

Answer 2

Common elements :

A scientific theory is an explanation or prediction of something in the Universe which is based on :-

• Observations

• Logic

• Proof

• Evidence

• Reasoning

The scientific theory should not be an assumption.

It should have a definite proof.

Another law or theory can be used in proving the theory.

Yes it should have enough logic to call it a theory.

Examples

• The theory of relativity

• Kinetic theory of gases

• Lewis theory

• Particle theory.

• The theory of Natural Selection

• The theory of Acquired Characters