A direct observation usually refers to observing a behavior and knowing exactly what is happening. For example, if I see a pigeon peck at some bread, I have observed it pecking. With direct observation, I cannot assume it is eating, that it is hungry, that it has any intention whatsoever. All I know is that it pecks.
Answer:
A) altering the nucleotide sequence of the DNA fragment
Explanation:
Gel electrophoresis is a technique to separate the DNA fragments on the basis of their charges and size. DNA fragments are made to migrate through a gel in an electric field. DNA has nucleotides and the presence of phosphate groups makes it a negatively charged molecule. In the gel electrophoresis, DNA fragment migrates through the gel toward the positive pole. Also, the gel slows down the large molecules more than the small molecules. Therefore, the DNA fragments are separated by size. However, the sequence of the nucleotide of DNA fragments does not affect the rate of their migration in the gel.
Answer:
They tend to move away from any stimulus be it light or mechanical.
Explanation:
The earthworm, upon encountering a stimulus that is mechanical in nature will turn its anterior end slightly away from the stimulus. Persistence of the stimulus may cause the worm to contract the longitudinal muscles of the opposite side to move the body around taking a new direction. And they also have the behaviour of tending to move away from any light stimulus.
