Variations within a species are known as:

families
varieties
speciation
none of these

Answer:

Variation within a species is known as speciation.

Explanation:

Speciation is a process through which the group of organisms belonging to the same species evolves into slightly distinct species. It happens as a result of the natural selection. These natural selections of species are due to the changes in the habitat due to habitat fragmentation, the introduction of a new niche, and genetic polymorphism. These natural selection of species or natural speciation are of 4 types:

1) Allopatric

2) parapatric

3) peripatric, and

4) sympatric.  

the level of progesterone is low at the pre-ovulatory phase of the cycle but it gradually increases and the levels are high at the luteal phase. if pregnancy occurs, the level of progesterone will be high throughout the pregnancy.

if egg is fertilized and the mother gets pregnant, progesterone starts preparing the uterus for the implantation. it starts building up the lining of uterus and make it hostile of the period of pregnancy.

plato users:

d.  

there was a variety of food available on island x, but there were only large seeds and nuts on island y.