When your body gets overheated. This is a negative feedback loop. The arteries/veins will dilate letting more blood pass through. Your face tends to get red because there is more blood flow towards the surface in an effort to cool off. This is also why you sweat.
Answer:
with each heartbeat,the heart pumps blood throughout our bodies,carrying oxygen to every cell,after delivering oxygen the blood returns to the heart the heart then sends the blood to the lungs to pick up more oxygen.
Answer:
Invertebrates can have bilateral or radial symmetry, or they can be asymmetrical. Bilateral symmetry means that the animal is arranged in the same way on both sides. Radial symmetry means the body parts are arranged in a circle around a central point.
