Answer:
D. The two students who have two fragments have one restriction site in this region.
Explanation:
The DNA samples from the cheek cells were subjected to digestion with a restriction enzyme. This enzyme is an endonuclease and cuts the DNA at a specific sequence only. This sequence is called a restriction site. If the restriction site is not present in the sample DNA, the restriction enzyme cannot cut it. The presence of one restriction site in the sample DNA would cut it into two DNA fragments.
Similarly, the presence of two restriction sites in each DNA molecule would obtain a total of three DNA fragments per DNA molecule.
At the base of the food chain
Answer:
during the Cambrian Period of the Paleozoic Era.
Explanation:
The Paleozoic is the earliest era (of three) of the Phanerozoic Eon and is composed of six geologic periods: the Cambrian, Ordovician, Silurian, Devonian, Carboniferous, and Permian (in that order from earliest to the latest). Fish first appeared about 530 million years ago during the Cambrian explosion.
We can control it. It's just that our world "leaders" seem to use use money and drugs for other things. It cost money to even make money, yet, people don't want to spend it.
