Answer:
In the nucleus of each cell, the DNA molecule is packaged into thread-like structures called chromosomes. Each chromosome is made up of DNA tightly coiled many times around proteins called histones that support its structure.
Explanation:
Chromosomes are thread-like structures in which DNA is tightly packaged within the nucleus. DNA is coiled around proteins called histones, which provide the structural support. Chromosomes help ensure that DNA is replicated and distributed appropriately during cell division.
Crossing over happens in prophase I when the homologous chromosomes are sy naps ed. The two inner chromoatids exchanges sections with each other. This means that after the exchange the inner two chromatids have new combinations of alleles than their parents had. The two outer chromatids still have the parental combinations.So there are more kinds of chromatids ready to go into the gametes than there were before. This is an increase in variation.
Answer:
B because it is talking about illumination which is lighting something up.
Explanation:
HOMEOSTASIS The cells can survive, if the temperature, pressure and chemical composition of their fluid environment remains constant. The surrounding environment of the body provides oxygen and nutrients required by all cells of the body.anation:
-Viruses can't reproduce by themselves. They require a host animal to do so.
-Viruses are not made of cells
-They can't keep themselves in a stable state (regulate temperature)
-They don't grow
-They can't make their own energy
Hope this helps :)