Why did photographers travel with their darkrooms in the 1800's?

(choose all that apply)

Question 3 options:

The chemicals had to be applied to a plate, in the dark.

It was too dangerous to mix photo chemicals in a downtown building

They sold advertisements on the sides of the big wagons and they made most of their money that way.

The photograph had to be made and developed while the chemicals were still wet

the chemicals had to be applied to the plate in the dark.

the photograph had to be made and developed while the chemicals were still wet

the chemicals had to be applied to the plate in the dark.

the photograph had to be made and developed while the chemicals were still wet

Explanation:

i think the answer would happen to be the letter b

because the bar never runs out

couples always argue

explanation:

the addition to geographic boundaries that might have  kept the people of the huang river civilization from traveling to far distance region is that they had learned about the other river valley civilizations but feared contact would bring invasion.

hope this .

plz give me brainliest!