"a mosquito in which the agent of diseases undergoes a a portion of its life cycle is known as a "

A mosquito in which the agent of diseases undergoes a a portion of its life cycle is known as a biological vector.

Explanation:

A malarial parasite undergoes half of its life cycle in a female Anopheles mosquito and the remaining half of the pathogenic phase in a human being. The parasite multiplies in the body of the female Anopheles mosquito and as that mosquito bites a healthy individual he becomes infected. Thus the mosquito serves as a vector that transmits the pathogen form a unhealthy individual to a healthy individual.

the backbone of the dna and rna compound is sugar phosphate.