Answer:
The immune system is made up of two armies of cells
Explanation:
I think so~~
<span>After a zygote undergoes cleavage division it is called a blastula. A blastula is a </span><span>spherical ball of cells that is created by cleaving the zygote.</span>
QUICK ANSWERNatural selection leads to evolution because the traits of those who are able to reproduce influence future generations genetics and gradually lead to these passed on traits becoming the normal state of being, thus causing the species in question to evolve. If a group of people have predominantly brown hair genes and have children, then by way of natural selection the dominant gene will increase with future generations, meaning that slowly in time this group of people will evolve to have mostly brown hair genes