Which of the following statements are fundamental to the clonal-selection theory of how the adaptive immune system functions? I) Each lymphocyte has a unique membrane receptor that recognizes one antigen. II) When the lymphocyte binds an antigen, it is activated and begins dividing to form many identical copies of itself. III) Cloned lymphocytes have slight differences and are selected by the spleen for removal if they do not bind an antigen. IV) Cloned cells descend from an activated lymphocyte and persist even after the pathogen is eliminated.
A. only I and III
B. only II and IV
C. only I, II, and IV
D. only II, III, and IV
Answer:
C. only I, II, and IV
Explanation:
Lymphocytes have specific membrane receptors. These receptors serve as binding sites for specific antigens. Binding of the antigen to these surface receptors triggers the propagation of lymphocytes which in turn form effector cells and the memory cells.
For example, the activated B lymphocytes divide into plasma cells and memory cells. The plasma cells divide and form a group of antibodies all of which have receptors for the antigen recognized by the parent B lymphocyte. The memory cells live in the body and begin the immune response when the same antigen ever enters. T lymphocytes also divide and form effector cells (active helper T cells and cytotoxic cells) and memory T cells.
You can see with the question alone that the plates involved is a oceanic and continental plate. With just that you can say that the answer is A. Another clue would be the <em>subduction</em><em />. This means that the plates converged, which makes it the type of boundary that occurred is <em>convergent.
</em><em />The answer again is A. <em>
</em>
A. Basically a hotspot forms above a mantle plume. A mantle plume is like a bit of magma from the earths mantle, but it’s like not near tectonic plate boundary things. (Sorry if that doesn’t make sense lol if you’re still confused I’d just look up a diagram of a hotspot)
B. A stratovolcano, those are just volcanos that are built with a bunch of lava and ash
C. Mt. Helens is formed on a subduction plate boundary, while a hotspot is formed because of mantle plumes, which are usually not on a plate boundary.
Hope this helps lol
Answer:
Folic acid
Explanation:
The congenital neurologic abnormalities refer to the abnormalities which are present in the infant at the time of the birth like neural tube defects in the given question.
There could be many factors responsible for this like consumption of drugs and alcohol, exposure to mutagens or carcinogens, inadequate amount of folic acid and many others.
Folic acid is a type of Vitamin B which is involved in the production of new cells so are advised to the pregnant lady during and before conception. Consumption of folic acid reduces the chances of birth defects.
Thus, Folic acid is the correct answer.
Paraplegia is paralysis that involves loss of motor and sensory control of the trunk and two extremities. In addition, paraplegia for the most part is the result of a spinal cord injury due to an accident or other trauma. Most common accidents contain motor vehicle accidents and falls in those aged over 65.
