1. The suns ___ keeps the planets in our solar system in orbit around the sun. 2. Comets are examples of bodies that complete parabolic or ___ orbits. 3. The orbits of all planets in the solar system are slightly elliptical with the exception of . 4. Kepler’s laws describe how objects move through space; ___ laws describe why objects move in this way. 5. Describe the differences between a geocentric model and heliocentric model. What model is the current Sun-Earth-Moon system based on?

What were the main components of earth’s earliest atmosphere? oxygen and ammonia hydrogen and helium oxygen and nitrogen hydrogen and nitrogen

What evidence could be used to convince policy makers to change a shipping lane from going through a whale breeding ground? information on the number of all whale species currently alive information on the number of all whales hit by boats in the given area information on the number of whale deaths in the world's oceans information on the number of whale offspring born every year. (a) scientists could collect and combine data on fish populations all around the world to show that their populations are declining. (b) scientists collect and combine data on fish populations all around the world to show that their populations are increasing. (c) scientists work together and use past data to show that fish populations are becoming locally extinct in some areas. (d) scientists work together and use past data to show that some fish populations are adapting to environmental changes.

What happens when two nitrogen atoms share electrons