What is a scientist who studies interrelationships between organisms and their environment

A scientist who studies the interactions or interrelationships between organisms and their physical environment is an Ecologist. 

Nimbostratus is the correct answer.
explanation: nimbostratus clouds are the type of clouds that are mostly likely present on gray, rainy day. these clouds produce continuous rain, snow and there is no thundering or lightening either.

The basic repeating unit of nucleic acids are known as nucleotides. a nucleotide consists of three distinct chemical groups.