Which statement most correctly describes the role of a connecting proteins a. it connects the carbohydrate tag with the correct cell response b. it attaches to the membrane, providing a matrix of support c. it creates a channel between the two layers of the bilayer membrane d. it serves as a link between membrane proteins on adjacent membranes

a "theory" a suggestion that is not 100 % accurate, or a figure. some people say its a theory because they of all the passed theory's about one subject. it depends sometimes theory might be accurate and sometimes they are.

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.