The artificial selection is a procedure of selectively breeding certain species of plants and animals in order to develop certain desirable traits. Artificial selection helps the humans to get the plants or livestock that are the most useful for them. Among the given options, the choosing of the sheep giving the most wool, mating of the goats producing more milk, and mating of the ducks to produce large eggs are all examples of the deliberate artificial selection.
But the using of the fishing nets that are catching only the large crabs is an example of indirect artificial selection as it leads to the increased population of small crabs.
Hence, the correct answer is 'option d'.
D. Watershed - a watershed is the area in which runoff, rivers, and streams run into a larger body of water
Answer:
Option (b).
Explanation:
Iguana and flying dragons are both reptiles. Iguana is a herbivorous lizard belongs to the order squamata. Flying dragons are known as gliding lizrds and belong to the genus<em> Draco. </em>
Iguana can easily be identified by their droopy skin, stocky stature and spines on their necks, backs, heads and tails. Iguanas may venture to the ground. Flying dragons has reduced tail, throat sacs color is different in males and females. Flying dragons used to live on trees, feed on the arboreal ants and will frequently venture in the ground.
Thus, the correct answer is option (B).
Answer:
A. Botulinum toxin possesses a heavy chain and a light chain, each of which takes part in the toxicity. The binding of the protein and its invasion within a nerve cell is permitted by the heavy chain. After the entry is permitted, the light chain functions like a protease and chops proteins, which would usually permit neurotransmitters to discharge out from the cell. This is basically a commotion of exocytosis or the discharging of neurotransmitters.
The acetylcholine, that is, the obstructed neurotransmitter generally conducts a nerve impulse to a muscle, allowing the muscle to contract. By inhibiting the neurotransmitter, the botulinum toxin results in its distinctive flaccid paralysis.
B. The small doses of the sterile, purified botulinum toxin when used in a medical setting as an injectable form prevent the release of a chemical known as acetylcholine by the nerve cells, which signal contraction of the muscles. By selectively interfering with the underlying tendency of the muscles to contract, the prevailing frown lines are smoothed out, and in the majority of the cases are almost invisible for a week.
