Answer:
D. Viruses can avoid activating the adaptive immune system if they do not change their surface antigens once they have been recognized by T and B cells.
E. People who were affected with the smallpox virus before cowpox virus were naturally immune to the smallpox virus because the viruses shared some common antigens and the memory cells that recognized cowpox antigens responded to smallpox antigens as well.
F. Helper T cells can kill cells that are infected with viruses and Cytotoxic T cells are known to activate B cells.
I have searched everywhere, but I have not found the proposals of the question, but I will explain to you what is the endoplasmic reticulum so that you can answer it.
The endoplasmic reticulum is a eukaryotic organelle located in the cytoplasm.
The endoplasmic reticulum is a network of membrane tubules (often interconnected) scattered throughout the cytoplasm of eukaryotic cells. Its membrane, which alone represents more than half of the cellular membrane system, is in contact with the nuclear envelope.
The endoplasmic reticulum can be:
Granular (or rough) (RER) that is to say associated with ribosomes.
Smooth (SER).
The granular endoplasmic reticulum is the place of synthesis (in the associated ribosomes) of the proteins secreted outside the cell and of the proteins and lipids constituting the membranes of the cellular organelles. Golgi, lysosomes, mitochondria, nucleus, ribosomes, vesicles ...). It participates in the correct folding of the proteins that have just been synthesized.
The smooth endoplasmic reticulum participates in cellular metabolism, synthesizing lipids and storing calcium.
An adaptation is an evolutionary process of a living species to live in its habitat or habitats and capable to reproduce. As the environment is not a permanent existence, the organisms have to keep adapting to the changing environment. Adaptation is a process which runs parallel to evolution. Today, if we see species like dinosaurs extinct, it is because they could not adapt to the changing environment. As we study evolution, we also notice the various stages man has been through before becoming the modern man. It is all a part of ecological adaptations.
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The best and most correct answer among the choices provided by the question is the second choice.
<span>The statement "On a sunny day, the air over a lake will be cooler than the air over the bordering land." would be TRUE regarding the behavior of air.</span>
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