Answer:
peptide antigens by MHC class II molecules
Explanation:
Helper T cells are activated by peptide antigens by MHC class II molecules. These antigens express on the surface of antigen-presenting cells (APCs). After activation, the T helper cells divide and secrete cytokines to assist the immune response.
(1)
Troposphere – This is the densest layer and where weather events occur
Stratosphere – This is where the ozone layer is found. Some high altitude aircraft cruise in this layer.
Mesosphere – Temperatures drop with altitude in this layer
Thermosphere – This is where most of the meteorites that enter the earth’s atmosphere burn up. This layer takes up most of the Uv and X-rays from the sun. Most satellites orbiting earth are in this layer
Exosphere – almost akin to space due to the thinness of the layer. Molecules in the layer often escape into space
(2)
A ‘pause’ is a transition between the above-mentioned distinct layers. The tropopause, for example, occurs between the troposphere and the stratosphere and the stratopause between the stratosphere and mesosphere and thermopause is found between thermosphere and exosphere.
(3)
A temperature inversion is a rise in temperatures with altitude in a layer in the atmosphere. One layer exhibiting temperature inversion is the stratosphere. This is due to the ozone layer that absorbs UV light. The upper ozone absorbs most of the UV light, than lower ozone, exciting the molecules and making the higher altitudes in the layer to be warmer.
(4)
The ozone layer protects life on earth from the high energy UV radiation from the sun. UV is capable of causing double-stranded break on DNA resulting in genetic mutations on organisms. Most of these would be lethal. The Ozone absorbs most of the UV before it reaches earth's surface. Ozone is formed when an oxygen molecule reacts with another oxygen atom to form an O₃. The oxygen atoms are made from the splitting of an oxygen molecule by UV light.
Learn More:
For more on the atmosphere check out;
brainly.com/question/13633485
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It also plays a key role in shaping organic molecules. Carbon<span> is very </span>important<span> to the chemistry of living things, mainly because of the versatility of structures it can form with itself and with other atoms</span>
Answer:
The phenomenon that explains the trend seen in the data is that the mosquitoes' evolution has led them to develop resistance to the compound.
Explanation:
This is a very common factor that we can see in insects. The effect of DDT on the species will have different levels of impact. One is going to be more vulnerable to the compound that the rest. However, after many times of exposition to the compound, a few survivors will develop resistance to the compound and their offspring is going to inherit that resistance. Making them increase the resistance over time.
Answer:
Humus
Explanation:
Also known as the uppermost layer of soil, that's for making soil more fertile due to its organic content.
