Which of the following are among the most common second messengers?
kinase and phosphatase
g proteins and gtp
kinase and phosphate groups
calcium ion and camp
gtp and gdp

The correct answer would be calcium ion and cAMP.

Secondary messengers refers to the intracellular signaling molecules which pass the signals from the receptors located on the surface of the cell to the target molecule present within the cell.

The secondary messengers can be classified into three major class:

Hence, from the given options, calcium ion and cAMP would make the correct choice.

answer; i believe the answer is hydraulic action;