How is it possible for different species to be so similar?

What happens whenever a net force acts on an object

To determine if a particular plant is homozygous or heterozygous, you would have to test cross with a

Consider the following reaction: 2h2 + o2 —> 2h2o a) what are the reactants in this reaction? b) what are the products in this reaction? c) how many molecules of oxygen are used in this reaction?