The word whereas is a conjunction that means “while on the contrary”. Explain whether the conjunction is used correctly in this sentence: My sister and I go to the local community center to swim, whereas my cousin also likes to swim there.

This use of "whereas" is not correct. Instead of using the term to contrast multiple situations, it is used to compare.

Explanation:

the language dates from the contacts of arabian traders with the inhabitants of the east coast of africa over many centuries. under arab influence, swahili originated as a lingua franca used by several closely related bantu-speaking tribal groups.