What is the slow, wavelike contraction that moves food through the digestive system?

Wich is not standing in the way of astronomers getting a good view of different star

Match the order of the levels of organization in nature with the correct description. example: atoms are fundamental units of matter= level 1levels- 2,3,4,5,6,7,8.now what levels are these? population consists of organismscells consist of moleculesecosystems consist of communities interacting with there environmentmolecules consist of atomsthe biosphere consist of all ecosystems on earthcommunities consists of populationorganisms consist of cells

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