Because they don't have a or any cells and have no DNA
Answer:
Explanation:
Blood vessels are vessels that carry blood through organs and tissues. The five types of blood vessels are: arteries, veins, arterioles, capillaries, and venules. The main function of blood vessels is to carry blood throughout the body.
It is asking for one trait or characteristic that can be seen visibly and environmental traits are characteristics caused by your geographic location for example African people have more melanin in their skin because they live closer to the equator and it protects them from getting sun burnt.
“Biomagnification or biological magnification is the process of accumulation of certain chemicals in living organisms to a concentration higher than that occurring in the inorganic, non-living environment.”
Human beings occupies the top place of most trophic level and we know that concentration of harmful chemicals increase as we go above the trophic level. Therefore human beings are most adversely affected by biological magnification.
Humans may also be affected due to the consumption of fish and shellfish.
