Help me with answers a and b

Legumes, a type of plant, require rhizobia, a type of soil bacteria, to survive since these organisms fix nitrogen during photosynthesis. rhizobia use the legumes for food. what would most likely happen to the legume population if rhizobia suddenly became extinct?

Which does not describe a physical change happening to water? water evaporating in the sun water reacting with nitrogen gas water freezing and being broken apart with a knife water heating up on a stove

What is the name of the idea that energy cannot be created nor destroyed