Speciation is the creation of a new species distinct from the original due to evolution.
I will walk through how this will work for you.
1. Animals of the same species living on either side of a stream can move from one side to another.
2. The stream changes into a river
3. Animals are now separated and must live apart
4. Environments on either side of the river change over time.
5. Animals due to natural selection, undergo change
6. After a thousands of years, two different of species form.
Hope this helps.
Sex linkage is a phenotypic expression where certain traits are expressed together with the sex gene. They are said to be linked to the sex genes. These include, Colour blindness, hemophilia among other traits. In this case if the mother is a carier (XcXC) and the father who is normal (XcY). This means the offsprings will be a carier daughter ,normal daughter, normal son and a color blind son.
Sharks, like all vertebrates, have bilateral symmetry. This
means they have symmetry across one plane (known as the sagittal
plane, and directly down the centre of their body), which means one
The are 4 glands in the endocrine system. The thyroid gland, pineal gland, parathyroid gland, and the pituitary gland.