Can humans breathe underwater

Answer 1

Water is not 100% transparent. And if we are talking about a river or the sea, it contains much more substances and particles than pure water. So, light suffers reflection and refraction when entering the water. So, after some meters under water, light cannot continue propagating. We need air in front of our iris to be able to focus. Our eyes werent designed to see underwater or there would be a clear membrane over the iris to be able to percieve depth underwater. Without either of these, you are only able to see a unfocused image. We need goggles or a mask to fix this.

Answer 2

Due to the inherent visibility and charisma of our fellow land-dwelling animals, it is often easy to forget that vertebrate life, and therefore the vertebrate eye, originally evolved in the water. Indeed, even those organisms that migrated to dry land found ways to keep their eyes bathed in salt water. So, as the ocean is the birthplace of the eye, it is useful to examine the intricate adaptations needed to see in a watery world. As anyone who has gone Scuba diving or swam in a lake with eyes open knows - there is not as much light underwater. Not only does water absorb light incredibly faster than air, but also scatters it in the three dimensions. Thus, the remarkable vertebrate eye evolved in a rather darkened realm where pressures changes significantly as animals move up and down. Fish eyes are quite basic in that they have a fixed iris and so adjust to different light levels in a different way from ours. However, the fish has a sensory line down each side which is very sensitive to sound and movement and augments awareness; a godsend at depths where there is little to no light at all.

Answer 3

No, humans cannot naturally breathe underwater. Our respiratory system is designed to extract oxygen from the air, not from water. Specialized equipment such as scuba gear is required to breathe underwater for extended periods of time.

Answer 4

People have survived being 100 meters underwater, but anything further than that would break bones and cause the lungs to collaspe killing them.

Answer 5

Yes, you can hear underwater. Since sound is the vibration of atoms, if a noise is made, you can still hear underwater since the water molecules still vibrate.

Answer 6

Yes If you try really hard

Answer 7

because they just cant

Answer 8

Yes.

Answer 9

YES