What are the uses of screw?​

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?

If the work required to stretch a spring 3 ft beyond its natural length is 15 ft-lb, how much work is needed to stretch it 27 in. beyond its natural length?

2.which choice most accurately explains what happens to the bonds between atoms when water changes to steam, and what becomes of the energy added during this phase change? when water changes to steam bonds between molecules are created. after reaching the boiling point, energy is used to change bond strength and change the kinetic energy of the atoms. when water changes to steam bonds between molecules break apart. after reaching the boiling point, energy is used to break bonds, but does not affect the kinetic energy of the atoms. when water changes to steam bonds between molecules are created. after reaching the boiling point, energy is used to break bonds, but does not affect the kinetic energy of the atoms. when water changes to steam bonds between molecules break apart. after reaching the boiling point, energy is used to change bond strength and change the kinetic energy of the atoms.