The idea that each living species descended from other species is called

natural selection.

Explanation:

Darwin defined evolution as "descent with modification," the idea that species change over time, give rise to new species, and share a common ancestor. The mechanism that Darwin proposed for evolution is natural selection.

protein makes up the building blocks of organs, muscles, skin, hormones and pretty much everything that matters in your body.

some choices are:

peanut butter

seeds

eggs

yogurt

meats

fish

so pretty much meat, dairy, nuts, and grains.