DNA nucleotides are joined by covalent bonds between the_of one nucleotide and the __ of the next (think backbone).

In some developing nations the percentage of the animal protein from fish in the diet can be as high as 25 percent.  about 85% of fish caught is used for human consumption.  the remainder is converted into fishmeal and fish oil. 

Ididn't do your trials but it is mostly likely because water is unique in the fact that it has surface tension.

Answer predation;