Which is an expression?
A. 1 = 3 - 2
B. 2 + 5 = 5 + 2
C. 4+ 3 < 9
D. 26

A. 1 = 3 - 2

Explanation:

What defines an expression?

expression - An expression is a sentence with a minimum of two numbers and at least one math operation. This math operation can be addition, subtraction, multiplication, and division.

So if we look at the letter options we can see that A is the best choice.

closed

conservation of mass states that total mass of the reactant and product before and after the reaction will stay the samehowever in a open experiment the mass may change as gasses could be escaping the containernot an insulated experiment as heat was transferred frim the reaction vessel to the surround area otherwise it would have been trapped

idk what a isolated experiment is ._.