Due to the overproduction of offspring with only finite resources, species begin to engage in competition for survival. In order to increase their chance of survival, certain species will begin to develop genetic variations that allow them survival advantages.
Answer:
Actin filaments return to their original positions (does not occur in muscle contraction, according to the sliding filament model).
Explanation:
Examples of active transport include the uptake of glucose in the intestines in humans and the uptake of mineral ions into root hair cells of plants.
Emperor penguins need lungs to breathe. In penguin lungs, air never stops. ... Once the air goes farther into the trachea it splits into two different directions into both lungs. To get the oxygen into the blood cells, it must come "within small distance of the penguin blood cells".
Veins don’t always conduct oxygen poor blood. The pulmonary vein brings reoxygenated blood from the lungs into the heart
