Answer:
The respiratory system is a biological system consisting of specific organs and structures used for gas exchange in animals and plants. The anatomy and physiology that make this happen varies greatly, depending on the size of the organism, the environment in which it lives and its evolutionary history. In land animals the respiratory surface is internalized as linings of the lungs. Gas exchange in the lungs occurs in millions of small air sacs called alveoli in mammals and reptiles, but atria in birds. These microscopic air sacs have a very rich blood supply, thus bringing the air into close contact with the blood. These air sacs communicate with the external environment via a system of airways, or hollow tubes, of which the largest is the trachea, which branches in the middle of the chest into the two main bronchi. These enter the lungs where they branch into progressively narrower secondary and tertiary bronchi that branch into numerous smaller tubes, the bronchioles. In birds the bronchioles are termed parabronchi. It is the bronchioles, or parabronchi that generally open into the microscopic alveoli in mammals and atria in birds. Air has to be pumped from the environment into the alveoli or atria by the process of breathing which involves the muscles of respiration.
Explanation:
There are choices for this question namely:
1. Sterile
2. Reproductive
3. Both
4. Neither
The correct answer is that flowers are a collection of reproductive tissue produced by flowering plants (angiosperms). The flower is a reproductive organ of the plant. It is composed of the male organ (stamen) which produces the pollen and the female organ (ovary) which receives the pollen. Once the ovary receives the pollen either from the same plant or from another through pollination, the ovule (part of the ovary) will then become the seed and the ovary will become the fruit. The seed is the "embryo" of the plant wherein if planted, it will grow to a new plant.
Answer:
The correct answer will be option-B
Explanation:
Meiosis is a way of cell division used by the organism to produce a large number of cells from a few parent cells. This is used to make the gametes of the body.
Meiosis produces four daughter cells from a single parent cell in two stages that is meiosis I and II. Each stage proceeds in four phases- prophase, metaphase, anaphase and telophase.
The reduction division of the chromosomes or the ploidy number takes place during anaphase I of meiosis I and not prophase I which is the initial phase of the division. Therefore, during prophase I the chromosome number of the cell remains the same.
Thus, Option-B is the correct answer.
Answer/Explanation:
Pollution during the industrial revolution caused trees to become covered with soot, making them darker. This dark appearance meant that the peppered moth, which usually had a light colour, was clearly visible against the tree. This meant it was easier for predators to identify. As a result, their numbers decreased because they were an easier target.
However, there was also a rarer form of the moth, which was dark in colour. These were initially very rare. However, because of the change in the tree colour owing to the industrial revolution, these moths were better suited to the environment, as they were more camouflaged against the dark tree. This meant it was easier for them to avoid predators, and so they were more likely to survive to reproductive age and pass on the genes that produce the dark colour. This meant that the dark moths increased in number.
Because the red eyes are recessive to black eyes, the parents could be heterozygous. Recessive alleles only show if two recessive alleles are combined. Thus the offsprings phenotypes of the gene would be C. Rr and rr
