I think the correct answer from the choices listed above is option A. For metamorphism to occur, the parent rock must be in solid form. Metamorphism is the alteration of the structure of a rock by factors like heat and temperature so it must be the material should be in solid form.
If the paramecium was not able to contract its contractile vacuole, it would be in danger of bursting. The cell would not be able to hold too much water. This would happen faster if the paramecium was in water with a low salt concentration because there is more water and less salt, so the water would accumulate faster.
Answer: Symptoms of potassium deficiency appear on the lower portion of the plant first with chlorosis (yellowing) at the leaf margins followed by necrosis (death). Potassium deficiency can be caused by soil pH, extreme liming or calcium rich areas of fields, lack of soil oxygen or true soil deficiency.