<u>Answer:</u>
<em>Earthworms are very sensitive towards the odor. </em>
They use it for locating the food in the soil. Because earthworms are dependent upon microorganism in the soil, they must be sensible for the <em>presence of any food around them if they do not respond the odor then they may die. </em>
Earthworms have the escape response so they quickly respond the external stimuli at the part they are stimulated. <em>With the increasing frequency of stimuli at the same part they slowly decrese the response towards it.</em>
A dependent variable is something you control, so probably drugs (as the researcher will ensure that they stay drug free)
Water cycle, also called hydrologic cycle, cycle that involves the continuous circulation of water in the Earth-atmosphere system. Of the many processes involved in the water cycle, the most important are evaporation, transpiration, condensation, precipitation, and runoff. Although the total amount of water within the cycle remains essentially constant, its distribution among the various processes is continually changing.
<em>i hope this was helpful..</em>
<em>if it was please mark me as brainliest </em>:)