What do you call identical parakeets setting on a roof edge?

My science teacher explained how the weather cycle works using an illustration. which is the best revision of this sentence?

Which key function of a business involves finding, targeting, attracting, and connecting with the right customers? (blank) is one of the key functions of a business. it involves finding, targeting, attracting, and connecting with the right customers

Asl may be used regularly in which field?