A fish species lives in the coral-like tentacles of a primitive invertebrate. Scientists believe that fish droppings and scraps of food provide nutrients for the invertebrate. What additional information would make this a mutualistic relationship?

The tentacles provide the fish with shelter from predators.

For a couple of decades, biologists knew the nucleus contained DNA and proteins. The prevailing opinion was that the genetic material was proteins, and not DNA. The reason for this belief was that proteins are more complex than DNA. This is because:  proteins have a greater variety of three-dimensional forms than does DNA.

Explanation:

Protiens have a greater variety of three dimensional forms than does the DNA

Protiens contain one or more polypeptides which are usually arranged in one of the following structures :

1)Primary structure

2) Secondary structure

3) Tertiary structure

4) Quaternary structure

These structures are maintained by Hydrogen bonding , Hydrophobic interactions , Disulphide bonds and ionic bonds )

DNA on the other hand is a double stranded molecule containing only hydrogen bonds between the nitrogenous bases and the covalent bonds within nucleotides. It is much simpler than protiens.