This is the structure of DNA and nucleotide is the phosphate group with sugar (the pink one ) and base that are 4 different bases : A, T, C, G and between these bases we have hydrogen bonds and you can see that always it like : C≡G
A=T :))) i hope that helps :)))https://www.google.com/url?sa=i&rct=j&q=&esrc=s&source=images&cd=&cad=rja&uact=8&ved=0ahUKEwiawYOO7-...
<u>Answer</u>: option B they have a random gene mutation that affects their fur colour.
<u>Explanation</u> :-
- <em>Variation</em> is the phenomena which occurs in all populations.
- These variations result in slight differences in the phenotypes of individuals .
- These variations only arise due to <em>random mutations </em>that arise in the individuals’ genome and then can be inherited by their offspring.
- There is always a probability of one particular trait to make the individuals survive better in the environment as compared to other trait.
- The individuals having the trait that helps them to survive better in the environment tend to survive more and leave more progeny. This is termed as <em>survival of the fittest</em>.
- Thus, according to the question it can be inferred that the dark fur colour arose due to a <em>random mutation </em>since it is the only source of variation. Since, in the given environmental conditions the mice having the dark fur colour were less susceptible to the predators they are better fitted to survive.
- The dark brown fur coat mice, survive better, leave more progeny and hence, increase their population with time. However, the orginal source of origin of this trait was a random mutation. Had this mutation not occured, the dark coloured fur mice would not have been there.
So, a <em>random gene mutation affecting the fur colour made the dark coloured mice first appear in the population.</em>
Answer:
The correct answer is The cells do not have proper receptor.
Explanation:
During paracrine signaling a signaling molecules are generated from one cell.The generated signaling molecule then binds to the receptor of neighboring cell to carry specific signal from donor cell to the acceptor cell.
But the signaling molecules will not bind to the cell that is producing it because that producing cell do not contain proper receptor to bind that signaling molecule.
The binding of signaling molecule to the receptor of its producing cell occur during autocrine signaling.
There is a valve at the meeting point between each ureter and the bladder prevents the back flow of urine from the urinary bladder to the kidney
The answer is Carbohydrates
