How are humans able to see rainbows?  

We see rainbows when the son is behind us and some type of water or rain is in front of us. When the sun light hits a raindrop it's refracted and is changed in direction.

(and we see them with our eyes ma or woma)

above statement is not a true statement about the open ocean because the open ocean has low levels of nutrients. most of the photosynthetic activity on earth occurs in the open ocean within the photic zone. organisms in the deep ocean are exposed to frigid temperatures and total darkness but it does not begin at the low-tide mark.