Which of the following is an example of symbiosis? a. barnacles living on a whale’s skin b. a tree obtaining nutrients from the soil c. phytoplankton absorbing the sun’s rays d. a blue whale feeding on zooplankton

A

Explanation:

A symbiotic relationship is defined as a relationship between two organisms, which can exist in the same ecological niche, without negatively affecting each other.

This can be used to describe the relationship between barnacles and whales. Where barnacles do not cause any harm to the whales on which they are attached, and the whales provide a way for the barnacles to be exposed to fresh nutrients in the water as they move, as opposed to being attached to a rock and not experiencing a great variety of nutrients.

So using the definition of a symbiotic relationship, we can conclude that out of the four options presented, only the example of the whales and barnacles is a true example of a symbiotic relationship.

Where a tree would obtain nutrients, this only presents one organism (the tree).

Where phytoplankton absorbs light energy from the sun, once again, only one organism is present (the phytoplankton).

A blue whale feeding on zooplankton is not symbiotic, because although they do occupy the same ecological niche, the whale is not providing any useful characteristics to the zooplankton.

the sugar-phosphate backbone forms the structural framework of nucleic acids, including dna and rna. this backbone is composed of alternating sugar and phosphate groups, and defines directionality of the molecule.