Why do siblings with the same parents still look different?

Siblings from the same parents can sometimes look so dissimilar, because the set of genes in one person can be immensely different from the other, despite having the same parents.

(I searched it up)

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.