<span>Hay fever is a manifestation of allergic reaction
from pollen, which is prevalent during haying season. Hay fever is commonly
known as allergic rhinitis caused by an oversensitive immune system,
particularly the lymphocytes, leading to a misdirected immune response. The body
undergo a sensitization when one develops IgE antibodies and develop a strong
TH2 response against pollen. Then, this newly develop IgE antibodies sticks to
basophils and mast cells with no signs and symptoms yet. However, when one is
expose again to pollens, mast cells will be activated and release mediators who
are responsible for immediate vascular and smooth muscle reaction. After this, local
clinical manifestation of hay fever will be observed. </span>
<span>The answer is Due to heating of the air by the engine exhaust. Contrails are formed when the hot exhaust of the plane engines is rapidly cooled by the cold air in the upper atmosphere. The water vapor in the engine exhaust, formed in the combustion of fuel, freezes immediately to ice crystals due to the low pressure and -36oC temperatures in the 8000 m altitude in which the planes cruise. </span>
Answer:
directional selection
Explanation:
Directional selection is the most common type of natural selection and occurs when some individuals with characteristics favorable to the conditions of the environment in which they live, have survival advantages over individuals who do not have this advantage, who end up dying.
Imagine, for example, a graph showing the directional selection in the same species of moths. Moths of the same species have white and brown collations, in summer, brown moths can camouflage themselves on tree trunks, while white moths cannot and are easily captured by their predators, which means that the amount of white moths decrease. In this graph, the population of white moths would be at a minimum, at the same time that the population of brown moths would be at maximum.
However, with the arrival of the reverse, snow begins to cover the trees, allowing white moths to camouflage themselves more easily. The brown moths, then, are very exposed to predators, causing their population to reach the minimum while the population of white moths reaches the maximum.
I'm at a loss between A & C but I'm not sure, I'd go with A
Answer:
[D] Pitch
Explanation:
The measure of how high or low a sound is called the pitch.
