need quick pls!

the most important element on earth is
-oxygen
-hydrogen
-water
-carbon

An exothermic reaction is conducted in an insulated calorimeter filled with water. the calorimeter is then sealed so that there is no heat exchanged between the contents of the container and the surrounding air. which of the following statements is true about the reaction?

Idon't really understand this can you me and show your work.☺☺[ chemistry b] subject [ electron transfer in lonic bonds]grade( 12)

The blackbody curve for a star name zeta is shown below. what is the peak wavelength for this star ?