<span>Controlled variable is a variable that was made constant in the research. That was because the controlled variables can influence the dependent or independent variable. If the variables is not made constant, it can alter the research result and made it invalid.
In this case, </span>the caffeine and alcohol intake might alter the physical activity or the blood glucose so it should be controlled.
Carbon 14 has a half life of 5,730 years. Scientists measure how much carbon 14 the rock has. For objects older than 50,000 years, scientists will test the age of the things surrounding it.
Answer:
Stephen Stearns states that natural selection doesn't mean the survival of the fittest organisms, but rather this mechanism is illustrated by the selective reproduction of the fittest. Natural selection can be classified into distinct types, including directional, disruptive and stabilizing selection, which are in turn based on sexual selection. These types of selection are driven by different outcomes that have different dynamics.
Answer: D. Ecosystem
Explanation: The ducks are interacting with trees and algae with are all part of an ecosystem.
The change would most likely result in a dip in #
