Fireworks exploding in the sky and giving off light are an example of a(n)

Which strategy is an example of how companies may upgrade themselves to meet changing customer preferences? a.doing door-to-door sellingb.using billboards to advertise the productsc. making online shopping services availabled.giving discounts on products

I’m doing some practice exam questions for biology, and i’m not sure how to do these 3 parts to the question.

Cells destroy body cells infected by a virus or bacteria. killer t t memory t none of the above