In my opinion, the best answer among the choices listed above is option D. The reason why scientists use models because they can <span>represent things that are too small to see. Models are used to describe and explain certain phenomena. Hope this answers the question.</span>
Answer:
Stay safe from predators in their natural environments. I'm pretty sure this is the answer but it might not be.
Explanation:
Answer:
Oxygen
Explanation:
The circulatory system gets oxygen from the respriatory system and circulates it throughout the body.
They use photosynthesis to turn sunlight, carbon dioxide, and water into carbohydrates.
When the organism become bipedal, they walk with 2 legs so there are 2 arms that were unused. Some of them try to use that hand by grabbing stick or stone, leading to tools. They start to think more to develop tools and their brain capacity become increased.
The ability to use stone tools will help in food digestion since it can break the food easier. This reduces the needs for bigger teeth/jaw.