A container holds an element and a compound that are not chemically combined. Is this an element, a mixture or a compound?

For a comparative or experimental investigation, scientists often make a testable about a scientific question, and then they test it in the investigation. a.control b.hypothesis c.procedure d.system

The vaccine in a flu shot contains weakened flu viruses. how does a flu shot work with the immune system? a. it destroys lymphocytes. b. it destroys macrophages. c. it activates macrophages. d. it activates lymphocytes.

Which of the following statements is accurate about evolution? question 10 options: natural selection only eliminates odd individuals. evolution means that a population never has changes in its genetic frequencies. mutations are always harmful. evolution means that a population undergoes changes in its gene frequencies over time.