If they test more than one variable, they wouldn't know if it was both variables or one variable that was responsible for any observed effect.
Answer:
Energy is transferred along food chains, however, the amount of available energy decreases from one trophic level to the next. The reason for this is that only around 10 per cent of the energy is passed on to the next trophic level. ... it is released as heat energy during respiration.
Explanation:
A condition in which the issue connecting muscle to bone becomes inflamed.
Earth's tilt on its axis affects the way heat is distributed on Earth's surface.
The Earth orbits the sun every 365 ¼ days. The Earth is tilted 23.5 degrees on its axis, which affects the distribution of the sun’s energy across the surface of the planet. More tilt means more severe seasons, that is warmer summers and colder winters where as less tilt means less severe seasons, that is cooler summers and milder winters.
Find out more on earth tilt at: brainly.com/question/818630
Answer:
it is the amount of soil, sunlight, and the music they listen to
control variables are the elements that are always constant and not changed throughout the experiment.