Answer:
C. Oceans are carbon sinks because they store more carbon than they emit.
Explanation:
Oceans are carbon sinks because they store more carbon than they emit. Most of the carbon is produced in the respiration process as well as burning of fossil fuels. This carbon moves to the atmosphere and dissolved into the ocean which is required by the vegetation of ocean. Due to this carbon, vegetation produced more food for the organisms. About 25% of all CO2 emissions are absorbed by the ocean. Source is the part of a plant where materials are produced e.g. leaves whereas Sink refers to the part of the plant where the substrate can be stored e.g. roots or stem for starch.
B. The Hubble Space Telescope
Bears, which overturn rocks to find the insects, consuming
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The structure of a typical antibody molecule
Antibodies are the secreted form of the B-cell receptor. An antibody is identical to the B-cell receptor of the cell that secretes it except for a small portion of the C-terminus of the heavy-chain constant region. In the case of the B-cell receptor the C-terminus is a hydrophobic membrane-anchoring sequence, and in the case of antibody it is a hydrophilic sequence that allows secretion. Since they are soluble, and secreted in large quantities, antibodies are easily obtainable and easily studied. For this reason, most of what we know about the B-cell receptor comes from the study of antibodies.
Antibody molecules are roughly Y-shaped molecules consisting of three equal-sized portions, loosely connected by a flexible tether. Three schematic representations of antibody structure, which has been determined by X-ray crystallography, are shown in Fig. 3.1. The aim of this part of the chapter is to explain how this structure is formed and how it allows antibody molecules to carry out their dual tasks—binding on the one hand to a wide variety of antigens, and on the other hand to a limited number of effector molecules and cells. As we will see, each of these tasks is carried out by separable parts of the molecule. The two arms of the Y end in regions that vary between different antibody molecules, the V regions. These are involved in antigen binding, whereas the stem of the Y, or the C region, is far less variable and is the part that interacts with effector cells and molecules.
