<span>The overall amount of water on our planet has remained about the same for two billion years.
True.</span>
The correct answer is: 4) Standing defenses are always present; induced defenses develop in response to a threat
Induced defense is defense that can be changed or invoked when needed. Induced defenses are slow to happen. When invoked, induced defense requires energy but otherwise doesn’t.
Standing defense is always there. It is use, for example when predation is a constant threat.
Answer:
The possible fate of the cell that it may turn cancerous.
Explanation:
The cells present in the body generally work in harmony. However, if a cell attains a mutation, it can make it proliferate in the case when it should not do, and make it thrive in the case when other cells are dying. Due to proliferation, the unusual cell produces more abnormal cells also known as cancerous cells. These cancerous cells become more favorable in comparison to the normal cells due to the phenomenon of natural selection. These cells eventually result in a lethal form of tumors.
In the normal cells, the destructed gene or the damaged cells get repaired easily, in case if the damage is worse the cell dies. A protein known as p53 helps in repairing damaged cells or kills them if the damage is too severe. But in the case of cancer cells, the p53 protein does not work appropriately as they possess a mutated or changed form of p53 protein. Thus, in the case of cancerous cells, the rate of repair lags behind the rate of mutation, which makes the cancer cells thrive and increase in numbers resulting in further destruction.
Answer:True
Explanation:Basically thymine diamers are mismatched pairs (thymine binds with another thymine instead of binding with adenine) and may lead to unwanted results so the mismatching can be repaired by using two methods which are as follows :
1-the PRE enzyme activated by blue light breaks the thymine diamer and some of the surrounding bonds the strand is cut and DNA polymerase then restores the normal base pairing
2-UVR system breaks dimer creating a gap when a gap is created and the molecules appear unpaired it is filled by proof readers hence restoring normal base pairing.
