All the above is correct.
Answer:
One of these is natural selection, which is a process that increases the frequency of advantageous gene variants, called alleles, in a population. Natural selection can result in organisms that are more likely to survive and reproduce and may eventually lead to speciation.
Explanation:
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:
No 15N/15N labeled DNA was observed in second generation
Explanation:
Meselson and Stahl were doing an experiment to find out the semi-conservative mode of replication of DNA. The first cultured bacteria in 15N medium which was containing a heavy isotope of nitrogen. The DNA synthesized here had more density. After that they transferred the bacteria to the 14N containing medium. When bacteria reproduced and new strands of DNA were synthesized, they observed the following -
- The first generation had hybrid DNA with 15N/14N strands
- The second generation had both hybrid 15N/14N DNA and 14N/14N DNA strands
- There was no 15N/15N DNA observed.
In this way they proved that one strand of DNA is kept conserved during the replication.
Answer:
Seafloor spreading is a process that occurs at mid-ocean ridges, where new oceanic crust is formed through volcanic activity and then gradually moves away from the ridge.
