Answer:
Valves
Explanation:
Circulation is maintained in the veins by the valves.
Veins are part of the blood circulation system and blood vessels that transports deoxygenated blood from parts of the body back to the heart. Within the veins are valves (flap like structures) which maintain circulation by ensuring that blood in the veins move in the proper direction toward the heart. Blood that is being transported through the vein usually have low pressure. The valves work by providing pressure to enhance the blood’s movement, and they also disallow backflow of blood as it moves through the body. Most of the veins, especially the ones located in the legs and arms usually have one-way valves.
Answer:
B.
burning of fossil fuels
it increase the amount of carbon present in atmosphere.
Answer:
Peer review is the best method in the scientific world to ensure that a scientific research has been made correctly with minimal errors.
In the scientific world, peer review can be described as the evaluation of the scientific researches by other scientists who have equal knowledge and competence with the scientists who made the research. Peer review is an excellent way to determine that all the steps performed were accurate or on point in the scientific research.
Hence, the scientists should go for a peer review to ensure that their conclusion is not biased.
