(2) Abiotic factors refer to light, water, temperature and air, and biological factors include small fish, snails, aquatic plants, fungi and bacteria.

(3) The equipment is sealed, but factors such as light and temperature can enter.

(4) Aquatic plants can carry out photosynthesis and live independently, while river snails do not produce organic matter and oxygen, so they must rely on plants to survive, and they will starve to death after a long time.

So the answer is: (1) Yes.

(2) Light, water, temperature and air; Small fish, snails, aquatic plants, fungi and bacteria.

(3) Yes; Light, temperature

(4) Aquatic plants can survive, but small fish and snails can't; Because aquatic plants can produce organic matter through photosynthesis, small fish and snails do not produce organic matter and oxygen themselves, and they must rely on plants to survive.