B. Nucleus because it contains the instructions for the cell
Loop Diuretics
These are diuretics that exerts effect on the loop of Henle. They are primarily used in heart failure, hypertension and edema. In contrast with Thiazides, loop diuretics are more effective in patients with abnormal kidney function. Loop diuretics inhibit the magnesium and calcium reabsorption in the thick ascending limb of Henle. Loop diuretics is highly protein bound. It has volume of distribution that is limited. This causes the diuretics to be secreted in the convuluted tubules to exert its function.
The answer is The Doppler Effect. It is named after the Austrian physicist Christian Doppler, who described the phenomenon in 1842.
I think the hydra lacks the specialized cells for touch and chemical detection. On the other hand earthworms have touch, light, vibration and chemical receptors along the entire body surface. Both of them are invertebrates (those animals without a backbone), they include insects, worms, jelly fish, spiders among other animals.
