They are accepted as true until they are proven false. Once a theory has been tested and it is wrong, then it is no longer true.
Answer:
A) Plants can’t photosynthesize at night.
C) Plants need ATP production for the entire day.
Explanation:
A) is correct. Photosynthesis occurs only in daylight hours.
B) is wrong. Photosynthesis peaks at noon when the sun is at its peak.
C) is correct. Plant respiration occurs both day and night.
D) is wrong. Photosynthesis begins at sunrise.
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.
Answer:
Adaptation
Explanation:
In this case predation is the selection pressure for natural selection in the mice population. Because the black mice stand out against the brown sand dunes backdrop, they are easily located and predated on by the hawks. Therefore, black mice have a lower chance (compared to brown mice) to reach reproductive age and pass down their genes to the next generation. With subsequent generations, therefore, there will be more and more brown mice in the population.
