Scientists have said that people that are showing no symptoms can still spread the coronavirus for several days. Knowing what you know now, how would you attempt to explain that to someone?

Explanation:

Well a person can be asymptomatic for loads of viruses not just coronavirus. There is no way of knowing if someone is asymptomatic without having a test done. Many asymptomatic people will go on to get a test and then show symptoms a few days or so later.

yes

no

blue is scattered more than other colors because it travels as shorter, smaller waves. this is why we see a blue sky most of the time.

they had the law tat factories that produces smoke cannot be built near residential buildings.

building of proper sewage system was done to ensure that the waste is carried away from the humans so that they do not get diseases from it.

also they built water systems to provide water in those areas which are drought prone.