1. The triple beam balance is a first- class lever; the fulcrum is between the two weights. As the liquid in the Petri dish evaporates, which way do you think that the balance pointer will move?
A. up
B. down
C. no movement

gravity causes stares to cluster i think so

first one is the correct answer

answer : a model is often used to explain and make things easier to understand when any scientific topic needs to be demonstrated and explained.

as in this case where a scientist wants to use a model to present the results of his detailed scientific investigation. he should do it as it will him to make the audience understand the concept in a much better way. also, it can be changed according to new scientific understandings.

the correct answer is:

a. formation of precipitation