Can you test a hypothesis that hummingbirds spend most of their waking hours feeding

Avariable that is not being directly tested during an experiment should be changed varied experimented controlled

How is the atomic number of a nucleus changed by alpha decay

What effect would average population growth have on land usage? a. urban use of land would rise to more than 30 percent of available land. b. industrial use of land would rise to more than 30 percent of available land. c. the percentage of available land used as cropland would stay the same. d. cropland would fall to about 10 percent of available land.