Which type of chemical reaction needs to absorb energy to proceed

Standing side by side ,you and a friend step off a bridge at different times and fall for 1.6s to the water below.your friend goes first,and you follow after he has dropped a distance of 2.0m.when your friend hits the water,is the seperation between the two of you 2.0m or more than 2.0m? verify your answer with a calculation.

Which composition of water moves to begin a deepwater current?

Which of these activities increases the amount of carbon in the atmosphere?