Answer:
Chordates
Explanation:
The notochord is a flexible, rod like supporting structure, running dorsally for almost the whole length of the body. This is a distinctive feature of a chordate / animals with a back bone (vertebral column) Such animals belong to phylum Chordata.
Mechanical stress applied to bone increases osteoblast activity in bone tissue, and the removal of mechanical stress decreases osteoblast activity.
Explanation:
Osteoblasts are cells , that are produced in the bone marrow and are responsible for formation of bones and bone matrix.
Whenever a mechanical stress is applied on the bones , a series of reactions are triggered. As a result the activities of osteoblast increases to synthesize more and more bone matrix to provide strength.
Again on the other hand a decrease in mechanical causes a decrease in the activities of the osteoblasts.
Answer AND Explanation:
<u>FACTORS THAT CAUSE GENETIC VARIATIONS</u>
- Crossing over. At the chiasmata during prophase I of meiosis, breakage may occur and exchange of genetic information may take place. New gene combinations which result in variations.
- Independent assortment. The arrangement of homologous chromosomes at the equator of the spindle during metaphase of the first meiotic division is random. These homologous chromosomes segregate into different daughter cells which contain different genetic combinations which brings about variation
- Fertilisation permits parental genes to be brought together in different combinations. This is the cause of variations in members of the same family.
- Mutation is the spontaneous change in the genetic makeup of an organism. These changes may be inherited by the offspring therefore beginning variation.
Answer:
D
Explanation:
They would be dying off, or leaving to get away from the disease
Answer:
yes
Explanation:
it is found in many forms in the natural world.