The rules of base pairing explain the phenomenon that whatever the amount of adenine (A) in the DNA of an organism, the amount of thymine (T) is the same (Chargaff's rule). Similarly, whatever the amount of guanine (G), the amount of cytosine (C) is the same.
Four abiotic factors in a prairie ecosystem would be soil, climate/temperature, water, and oxygen. Hope this helps!
Activation energy is the minimum quantity of energy that the reacting species must possess in order to undergo a specified reaction.
for example , striking a match on the side of a matchbox provides the activation energy, in the form of heat produced by friction.
I believe that the answer to your question would be A. Heart Begins.
There are many forms of VIF and each forms are made for different purposes. basically, you just extract a female egg and a sample of the male sperm, bad sperm can be separated via by adding specific chemicals. The sperm will then be transferred into the egg and the egg is transferred into the women. (This is ICSI) There are other forms under the category of IVF but this is one of the example. (ICSI only deals with male infertility)