Answer:
Telomerase
Explanation:
Repetitive regions at the ends of Chromosomes are known as telomeres and these are crucial for chromosomal stability. There is no gene present and they provide protection to internal parts of chromosome. The telomeres are eaten up slowly by ‘DNA REPAIR MECHANISM’ after many division cycles, which is considered as ageing. That why, a cell can divide only certain number of times.
Some cells have ability to express an enzyme telomerase that maintain the length of telomere. The telomerase enzyme contributes to cell immortality by rebuilding the damaged telomere. Thus telomerase enzyme is necessary for cancer initiation and survival of tumor. Telomerase enzyme can make its own DNA by using its RNA as template
. It extends the overhang strands of DNA by using a comlementary DNA.
The thalamus receives messages from muscles, tendons, joints and structures in our ear to control balance, coordination, movement and motor skills.
Answer: 28
During anaphase, chromosomes are separated. However, all the chromosomes are still in the cell as the cell has not undergone cytokinesis. Therefore, 4 sets of chromosomes will be found in the cell.
Through natural selection it happened over many generations and it was gradual, not a sudden change in the founder species. One bird was randomly born with a fatter beak and so could eat a seed that was harder to crack, this meant he lived longer than the other birds or was fitter, so bred more and so more of the offspring had this slightly larger beak. This continued and the birds moved to the islands with their ideal seed and kept getting fatter beaks etc until they were no longer the same species (this is when they can't breed to produce fertile offspring).
Answer:
D.
Explanation:
A. Is wrong because the moon blocking the sun is a solar eclipse while the Earth blocking sunlight to the moon is a lunar eclipse.
B. Is wrong because solar eclipses occur during a new moon.
C. I s wrong because the inverse is true.
