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Answer:
The answer is actually B) Memory T. Memory T cells rapidly produce large numbers of effector T-cells when re-exposed to their antigens, which provides the immune system  memory against past infections.
 
        
                    
             
        
        
        
 Answer:
When plants and animals die, organic molecules also undergoes decomposition and this causes the incorporated phosphates to go back to the soil or bodies of water.
Explanation:
Phosphates are naturally related to <u>"phosphorus."</u> <em>They play a vital role in the life of animals and plants. </em>Phosphorus can be commonly be found on the earth's land and water (although the land has a smaller amount of it). <u>Plants naturally absorb phosphate from where they're growing. Animals take up phosphates by eating plants.</u> The phosphate that plants get from the soil are considered inorganic. They only become organic when it is incorporated into the plants DNA (since this is an organic molecule).
So, this means that if there's a sufficient amount of phosphate, there will be more plants on earth as it is also important in the process of acquiring nutrients. 
When animals and plants die, all of the organic molecules such as phosphate also breaks down and thus, it falls back to the soil or bodies of water. Then, they are ready to enter another Phosphorus cycle.
 
        
                    
             
        
        
        
Answer:
Natural selection, the keystone of evolution, can switch direction in a matter of months, a novel experiment on lizards reveals.
 
        
                    
             
        
        
        
Answer:
Soil erosion. 
Explanation:
No-till plowing can be defined as a farming method or technique which typically involves planting crops (seedlings) without tilling the soil rather the farmer would only open a narrow or very shallow trench of sufficient depth and width to cover up the seedlings. Thus, the no-till plowing makes crop residues to be left on the soil and by extension preventing soil erosion through the absorption of water by the crop residues. 
Hence, by leaving crop roots in the ground and stalks on the surface, no-till plowing helps prevent soil erosion.
Additionally, the water retention ability of no-till plowing is usually a boon to farmers because it slows down evaporation and serves as a good protection for drought-stricken environments.