The answer might be B because fat is very unhealthy and having the least amount is healthy, but you must have enough fat in your body (not so that you'll be obese, etc), you must have the right amount of fat. But, I'm not so sure. Please let me know.
The basic unit of classification of living things is species. species is the smallest unit containing members which have the largest number of features in common and usually interbreed among themselves.
Thus, the group of deer describes a specie since they can interbreed freely and are similar in characteristic features.
Cholera occurs when the G protein cannot hydrolyze GTP to GDP so the G protein is always active. This causes water and salt to leak out causing diarrhea and eventually death by dehydration.
The waves move outwards from where the rock hit. When the waves pass the wood, it bobs up and down. In the case of the falling dominoes, the movement of the dominoes was in the direction parallel to the movement of the wave, longitudinal.