Answer:
b. it involves a physical exchange of segments from homologous chramosomes.
Explanation:
Crossing is a phenomenon involving homologous chromatids. It consists of the breaking of these chromatids at certain points, followed by an exchange of corresponding pieces between them.
Exchanges cause new gene sequences to appear along the chromosomes. Thus, if on a chromosome there are several genes combined in a certain sequence, after the occurrence of crossing the combination may no longer be the same. So when thinking about crossing, it is common to analyze what would happen, for example, about the combination of the allele genes "A" and "a" and "B" and "b" in the pair of homologues.
Answer: 1. larva, 2. nymph
Explanation:
In complete metamorphosis the precursor of insect undergoes with four distinct stages to develop into complete adult insect. These are egg, larva, pupa and adult.
In incomplete metamorphosis the insect precursor hatches from an egg and then goes through several nymphal stages similar to adult.
Therefore, in complete metamorphosis the immature stage is called as larva and in the incomplete metamorphosis the immature stage is called as nymph.
Wood is a renewable resource
Answer:
They would be deficent in iron and vitaman B12
Explanation:
Answer: c. iris – controls the pupil
Explanation:
The iris, a structure which is primarily made up of smooth muscles. These smooth muscles surrounds the pupil. The light enters the eye through pupil which is a black hole present in the middle of the eye. It allows the light to strike the retina. It controls the size of the pupil this way it helps in regulating the amount of light entering the eye. The pupil becomes wider in the darkness and becomes narrower when the light intensity is more. These actions are controlled by iris.