The right answer is <span>Refractory period.
At the moment when the action potential is emitted, the fiber being depolarized, it is impossible to depolarize it again. It is, therefore, necessary to wait until the membrane potential returns to a value below the critical threshold in order to be able to excite it again. We are thus led to distinguish two periods that characterize its excitability.
An absolute refractory period: during which any stimulation, even supraliminal, is ineffective since the fiber is already depolarized.
A relative refractory period: during which a second action potential can be omitted provided that the depolarization produced by the excitation reaches the critical threshold, which implies that it is more important since the value of the resting potential has not been restored yet.</span>
The respiratory system works directly with the circulatory system to provide oxygen to the body. Oxygen taken in from the respiratory system moves into blood vessels that then circulate oxygen-rich blood to tissues and cells.
Answer:
True
Explanation:
The Drosophila like the mammals possess X and Y chromosomes but as in males in which the XX is female and XY is male, the sex In Drosophila is not determined by the presence of Y chromosomes as a male determining factor are present on the autosomes.
However, the Y chromosome is important for males as they are involved in the formation of the sperms therefore the presence of Y is important. In the given question if the allele is present ion the Y chromosome which can reduce the size therefore the allele is passed on to the males only ans no females.
Thus, true is the correct answer.
the fly is female (Bridges 1921, 1925). Thus, XO Drosophila are sterile males. In flies, the Y chromosome is not involved in determining sex. Rather, it contains genes active in forming sperm in adults.
Answer: The correct answer is option C. To form RNA molecules from DNA molecule.
Explanation:
The main function of transcription is to form ribonucleic acid (RNA) molecules from deoxyribonucleic acid (DNA) molecule present in the nucleus. In transcription, small part of DNA is copied and attached to the RNA molecule with the help of enzymes i. e. RNA polymerase.
They would have had to have received the gene from both their mother and father. This gene is carried on the X chromosome and is only shown in females when it is present on both.
