Answer: Option D.
Crystalline and rigid.
Explanation:
When liquid freezes to ice, it becomes solid and this is crystalline and rigid because a solids for crystals which means solid atoms, molecules or ions are orderly arranged in structures which form of crystal lattice in all sides. The structure of solid becomes rigid , it does not take the container shape like liquid and it does not expand also like liquid. it volumes reduces.
Since the corals lack the zooxanthella that are found in tropical coral reefs because the zooxanthella require sunlight and there is no sunlight, the corals are built upwards instead of across. The polyps build the coral this way because they are filter feeders. The correct answer is C, filter feeders.
Producers are at the bottom or beginning of the food chain because they produce their own food. producers do not eat other organisms unless there are exceptions. consumers eat other consumers and also eat producers.
Plant! The membrane controls what goes into and out of the cells.