Answer: The 1st one is B. I'm pretty sure the 2nd one is A. and the 3rd one is D.
Explanation: I hope this helped, although I'm not sure for the second one
The gravitational potential energy
gpe = mgh

Benzene was a ring of six carbon atoms! This was the structure that made him well known around the world
Answer:The correct options are:
1. A system is a group of objects analyzed as one unit.
2. Energy that moves across system boundaries is conserved.
Explanation:
A system is defined as group of interrelated or interacting items existing as a single unit or a whole to achieve a specific objective.Energy lost by the system is equal to the energy gained by the surroundings.
Two statements are true about a system:
- A system is a group of objects analyzed as one unit.
- Energy that moves across system boundaries is conserved.
Answer: Physical changes only change the appearance of a substance, not its chemical composition. Chemical changes cause a substance to change into an entirely substance with a new chemical formula. Chemical changes are also known as chemical reactions.
Explanation: