What are the stages of the life cycle of a star? What happens at each of these stages? How do we collect information about stars?

Identify the type of energy used in each action. the flexing of an arm muscle: a signal transduction process by a neuron: a ball at the top of a hill: 1. electrical energy 2. mechanical energy 3. gravitational potential energy

What is the following best defines climate?

Why do leaves change color in the fall? green pigments break down and no longer mask the color of chlorophyll. chlorophyll breaks down and no longer masks the colors of other pigments. red- and yellow-colored pigments grow and mask green-colored chlorophyll. green-colored chlorophyll breaks down and turns red and yellow.