Answer:
Cells are similar to factories. To stay alive and function properly, cells have a division of labor similar to that found in factories. All eukaryotic cells are composed of a plasma membrane, a nucleus, and cytoplasm. These structures can be compared with a factory's departments.
Explanation:
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.
Answer:
D. any natural process that threatens human property and human lives.
Answer:
It is located in the asteroid belt between Mars and Jupiter
Your carbon atom enters the leaf as CO2 (carbon dioxide) from the atmosphere. <span>In the leaf, chlorophyll uses the energy from the sun to convert CO2 and H2O to the sugar glucose, C6H12O6. Your carbon atom is part of this molecule; it is now one of the carbons in the glucose. </span>
<span>Next, the glucose carrying your carbon atom is sent down the phloem tissue of the carrot plant to the root, which is the carrot itself. </span><span>Enzymes in the carrot root connect the glucose molecule with your carbon atom into a chain with other glucose molecules, forming cellulose, or plant starch, and there you go. Your carbon atom went from being part of an atmospheric gas to a starch via photosynthesis and starch formation in the root. </span>
<span>I hope that helps!</span>
