Question

why do whales and dolphins often comeup to water surface?

Answer 1

Hey mate here's your answer
The whales and the dolphins come out of the water to breathe
HOPE IT'S HELPFUL PLEASE MARK IT AS BRAINLIST

Answer 2

WHALES AND DOLPHINS OFTEN COME UP TO WATER SURFACE BECAUSE THEIR LUNGS ARE RESPIRATORY ORGANS FOR THEM .

SO, THEY COME OUT FROM WATER AND BREATHE AIR.