1. A person is sitting by the beach and a mosquito bites them. Could they contract HIV?
2.A person sits on a public toilet at Wal-Mart ®. Could they contract HIV?
3.Two people are in a fight outside a football game. Both are bleeding. Could they contract HIV?

1. no

2. no

3. It depends on if one of them is a carrier of the virus and the other comes in contact with the blood

before, trains worked using the steam engine. thus, it uses heat so it is crucial to apply heat balance. the steam engine absorbs energy during the stage of boiling water. so, this is the endothermic reaction. when the steam is used to work the piston, it has to release this energy through running the train. the excess energy is released as an exhaust to the chimney. this is the exothermic process because it releases energy to the surroundings.