Gene flow does not promote speciation, whereas season of fertility, natural selection, and genetic drift do.
Glacier because ice sheet and stuff and science ill explain more in the comments
Tetraploidy will occur.
<h3><u>Explanation</u>:</h3>
The process of sexual reproduction is very necessary to maintain the genetic setup of the species over the races.
The normal chromosome content of a cell is called diploid state of cell. Its represented by the expression 2n. The cell division that takes place before the gamete formation is called meiosis. This cell division makes the chromosome number of the cells halved. So haploid cells are produced. Its represented by n.
Now as the gametes fuse, both the n becomes 2n and diploid state is regained.
But if the meiosis don't occur in the gametes, the gametes will remain 2n. So after fertilization, it becomes 4n. This state is called tetraploidy.
Answer:
1. To produce the circular motion, they used another concept known as the magnetron.
2. Set the water in circular motion with a hand or spoon.
3. Start from the center and work outward, using broad, circular motions.
<u>(I hope this helps! :)</u>
Answer: Possession of Valves
Explanation: Veins possess valves which ensures that blood flows in only one direction. Valves helps blood to flow back to the heart against gravitational force.
Arteries don't have valves because the pressure originating from the heart is capable of causing the blood to flow in one direction.