The answer is D. receiving blood from the gills
A common way that humans pollute water is through the addition of nutrients (fertilizers and sewage) to water as nonpoint source pollution. These added materials are full of nitrogen and phosphorus, two nutrients that encourage the growth of aquatic producers, such as algae.
Answer:
A it investigates the super natural.
Answer:
Leukocytes are also called white blood cells. These cells have a nucleus, unlike red blood cells that lack a nucleus. Also unlike red blood cells, white blood cells do not contain hemoglobin, which means they're not involved in the transport of oxygen.