Proteins are constructed from MRNA, so why is it said that information specifying traits of organisms is encoded in DNA?

Because the mRNA are produced from DNA.

Explanation:

DNA, which encodes the genetic information needed for the survival and growth of living organisms, is said to be the BLUEPRINT OF LIFE. This is because DNA stores the information for specifying the traits of an organism. Although, according to this question, it is very TRUE that protein molecules are constructed from mRNA, but the mRNA are synthesized from DNA.

The gene, which is found in the DNA molecule, undergoes expression in two ways namely: transcription to mRNA, and translation to amino acid or protein. This protein is responsible for the traits exhibited by organisms. However, the whole process begins with DNA.

well for one plants are always the producer, so a is the answer. a wolf is more of the consumer(predator) and the deer is the prey so i know those two are out of the question. also mushrooms are fungi/fungus so a is the producer.