Which scenario describes an interaction between two of Earth's spheres? Water flows from a stream to a lake.
Gravity moves rocks to another location.
Lions use energy to catch other animals for food.
Bears dig big holes in the ground to protect their young.

The rate constant for the reaction below is 6.2 x 10−5 mol l−1 s −1. if the initial concentration of a is 0.0500 m, what is its concentration after 115 s?

Can anyone explain 1. review your spectrometry data and use the known elements to identify the star's composition. which unknown elements make up this star? justify your element selections. 2. in parts i and ii of the lab, what happened to the electrons of each element to produce the different colors of light? explain your answers using important terms from the lesson and information provided in the laboratory. 3. stars composed of heavier (more massive) elements are often slightly older than stars made predominantly from hydrogen and helium. based on your data, is the newly discovered star a younger star? explain your answer.

These traits describe either a chemical or a nuclear reaction. which statements describe a nuclear reaction? check all that apply. involves the loss, gain, or sharing of electrons may involve a change in total mass involve relatively low energy changes occur outside the nucleus involve very high-energy changes involve changes in nuclides when decay occurs