Give two ways in which bacteria are useful to us and two ways in which they're harmful ?

sorry, but you do not have posted the diagram.

not always but somethings can be reproduced in a laboratory.

essentially, one bacterial cell splits into two daugurer cells. bacterial offspring don't need or get care from their parents because they are in a sense their own parents. that said, some bacteria can and do depend on other bacteria especially in harsh environments such as bacterial microfilms in hot water tanks.