If an object is released from an altitude of 1000m, its velocity equals 9.8 m/s downward after a second

Astudent creates a model of a closed ecosystem by filling a glass tank half full with water, then adding 10 snails and two small aquatic plants. the next day, all the snails are dead. what is the most likely cause of their death?

What are the similarities & differences between a thermistor and a light dependent resistor in physics?

If you put a helium-filled balloon in the refrigerator, what will happen?