Simply use a stop watch. Begin the stop watch when the necessary elements have been added and stop it immediately as soon as it turns purple. Repeat the process a few times to make sure the timing is accurate.
C. Providing the lungs with nutrients
<span>The first step is to pose the question or problem to be investigated. This is followed by observations, which help to form a hypothesis to explain the observed phenomenon or effect.</span>
Because predator species often will switch its prey as one prey species becomes less abundant.
Why this is so should be obvious - because it's not in the interest of predators for the prey species to completely die out as it would effectively also mean that they would die out due to not having enough food to eat.
