The universe could be considered an isolated system because?

The answer to your question is  It's a physical system that is not affected by any other system. They don't really exist, other than the universe. You might incorrectly state that an object is space is isolated from everything else, and it does seem that way. It's still affected by gravitational fields, but negligibly. However, you look at the universe which you define to be everything ever. There is nothing else that exists to interact with it, so it is an isolated system.

This answer is a physical system that is not affected by any other system. You might incorrectly state that an object is space is isolated from everything else, and it does seem that way. It's still affected by gravitational fields, but negligibly. However, you look at the universe which you define to be everything ever.

The answer to this will be from your lab notes/procedure. it would be best to ask another student who participated in the lab as we do not know what was done, what enzyme or if the temperature is celsius or fahrenheit. if i were to guess though i'd say the rate stopped due to enzyme denturing at high temperature