Genetic variation<span> occurs </span>mainly<span> through DNA mutation, gene flow (movement of genes from one population to another) and sexual reproduction</span>
Food enters the stomach during the third stage of digestion, hope this helps.
As you can see in the picture presented below, the three classes of water have distinctive traits.
Pure substances contain only one element, they are not mixtures of different things.
The homogeneous mixtures have multiple elements, but they are so well blended together that you can't easily observe or separate them.
In heterogeneous mixtures, we can easily differentiate between different elements of the mixture.
It is c. White blood cells
It is false cause the embryo develops the baby into whatever mammal offspring is being born