Please help
According to Hess’s theory, what might happen if the magma under a mid-ocean ridge cools?

The magnetic stripes might reverse direction.
The deep-ocean trench might become deeper.
The crust at the ridge might form more quickly.
The plates on either side of the ridge might stop moving.

Acalorimeter is to be calibrated: 51.203 g of water at 55.2 degree c is added to a calorimeter containing 49.783 g of water at 23.5c. after stirring and waiting for the system to equilibrate, the final temperature reached is 37.6 degree c. specific heat capacity of water (s = 4.18 j/g∙degree c). calculate the calorimeter constant. (smδt)warm water = -[(smδt)cold water + (calorimeterδtcold water)]