Aquifer recharge is water that moves from the land surface or unsaturated zone into the saturated zone. Quantitative estimation of recharge rate contributes to the understanding of large-scale hydrologic processes. It is important for evaluating the sustainability of groundwater supplies, though it does not equate with a sustainable rate of extraction. Where contamination of an aquifer is a concern, estimating the recharge rate is a first step toward predicting solute transport to the aquifer. Recharge may cause a short- or long-term rise of the water table. Artificial drainage, e.g., with horizontal porous pipes buried at a chosen depth, is sometimes used to maintain a minimal thickness of vadose zone for agricultural or other purposes.
Recharge rates vary considerably in time and space. Recharge often occurs episodically in response to storms and other short-term, high-intensity inputs. For a given amount of infiltration, temporal concentration enhances recharge because it entails shorter residence times for water in the portions of the soil from which evapotranspiration takes place. Similarly, a larger fraction will become recharge if it is concentrated in narrow channels such as fingers or macropores, not only because this tends to hasten its passage through the unsaturated zone, but also because the water then occupies less of the volume of soil from which evapotranspiration takes place.
There is variation in DNA.
Answer:
The correct answer is option d. "Its conformation will change when both an ion and a small molecule bind to it".
Explanation:
The secondary active transport is a form of active transport at which a ion (typically Na+ or H+) is transferred down its electrochemical gradient to the uphill movement of another molecule. Secondary active transport takes place by the conjunctive work of membrane-bound proteins and sodium–potassium pumps. During secondary active transport, both of these proteins change its conformation when an ion and a small molecule bind to it. This change in conformation makes possible that the ions and the small molecules pass through the membrane.
Answer:
The correct answer will be option-C
Explanation:
The CsCl gradient centrifugation in Meselson Stahl experiments is done to separate the bands of the DNA containing isotopes on the basis of difference in the density.
In the experiment, bacterial cultures were grown in the medium of 15N and 14N but if we repeat the experiment with P32 and P31 instead of 15N and 14N and centrifugation is performed then the banding pattern will be the same as of the previous experiment as the method of the replication is same that is semi-conservative.
Thus, Option-C is the correct answer.
