Why has blood been the most essential component of life in human beings?

@Lostpoet Or maybe their blood is colorless having the characteristics of ocean water. Likewise Ants have no blood, one can say but some fluid is still there which acts like blood.

@Peterpaul17 I think you're right they do have hemoglobin but no red blood cells

@Lostpoet Wouldn't it be weird if when we killed fish, they would bleed? I feel sorry for all animals that suffer, then die.

@LadyGrace Fish do bleed. I've caught and gutted a few fish before i tried to become a vegetarian. I felt guilty pulling them out of the water and then killing them. They look so cool and effortless swimming in the water.

All animals(including people) suffer and then die it just takes us 80-100 years to do it. I think maybe it's punishment for killing us kill Jesus.