1. how are stars important to the milky way?
2. how has the knowledge and perception of the universe changed over the past century?
3. what effect does dark energy have on the universe?
4. how is matter important to the universe?
5. what do scientists believe may be the fate of the universe? which theory do you feel is the better explanation of what may happen? why?

The body is protected against harmful flu viruses by

1. variations in a population of moths allow for some of its members to be able to adapt to environmental changes. the better adapted of the moths will be able to survive the change and thus prevail as the “fittest” of the species. (a) describe three mechanisms in which variation can occur within a species population. (b) explain which mechanism or mechanisms would be responsible for the survival of a population of peppered moths better than white moths in an environment affected by industrial soot. justify your answer.

Match each description to the level of organization