WHY DO WHALES AND DOLPHINS KEEP COMING UP TO THE WATER SURFACE?

to breathe

for respiration

 it is because  they have nostrils insted of gills . Thus, have tocome up for respiration.

they have to come to surface of water cause they have tio respirate and they can  store oxygen  for only  min.

Whales and Dolphins keep coming up to the water surface because they don't have Gills like other fishes which helps them to take the oxygen dissolved in water.

 dolphins do not have gill like other fishes .so they come up to the water surface to give out the carbon dioxide.

yes it's true that dolphins or whales do not have gills and can not breathe to the oxygen dissolved in water and hence need to come to the surface of water toinhale oxygen . They can remain in water not for a long time without breathing out.

whales and dolphins do not have gills instead they have blowholes( small holes on their head)

so in oder to breathe they come to the surface but they can also go on without water for a long time

they need oxygen to respire. They also don't have gills so time to time they have to come out to take oxygen

Theyneed oxygen to respire because they dont have gills