Pi and sigma bonds
Pi is double bonds and sigma is single bonds
Lowercase b is the allele that goes in 3
The purpose of a dichotomous key is to identify organisms
Explanation:
A dichotomous key is a kind of a tool that guides to classify and identify different organisms.
This key as the name indicates - dichotomous- consists of two parts or options to identify a species.
The method utilizes a series of questions/answers with two possible outcomes.
Taxonomically, a dichotomous key is used to basically identify a species or an organism by its scientific name.
All of the natural elements like the plants, animals, birds, etc are identified using this key.
Types of dichotomous key includes nested, linked, branching tree etc.
Acid rain, if I understand the question correctly.