Given a scientific passage and an answer, generate a question for the given answer.

[Q]: Passage: The body of a cnidarian consists of two cell layers, ectoderm and endoderm. The cells surround a digestive cavity called the coelenteron (see Figure below ). Cnidarians have a simple digestive system. The single opening is surrounded by tentacles, which are used to capture prey. The tentacles are covered with nematocyst cells. Digestion takes place in the coelenteron. Nutrients are absorbed and gases exchanged through the cells lining this cavity. Fluid in the coelenteron creates a hydrostatic skeleton. Answer: tentacles
[A]: Cnidarians have a simple digestive system with a single opening surrounded by what type of structures, which are used to capture prey?

[Q]: Passage: The hypothalamus and pituitary gland are located close together at the base of the brain. Answer: the brain
[A]: The hypothalamus and pituitary gland are located near the base of this organ?

[Q]: Passage: To allow the plant to retain water and exchange gases, small pores (holes) in the leaves called stomata also evolved ( Figure below ). The stomata can open and close depending on weather conditions. When it's hot and dry, the stomata close to keep water inside of the plant. When the weather cools down, the stomata can open again to let carbon dioxide in and oxygen out. Answer: stomata
[A]:
What is the name for the pores in leaves that allow a plant to retain water or exchange gases?