Answer:
Closed the first one
Explanation:
In amphibians, reptiles, birds, and mammals, blood flow is directed in two circuits: one through the lungs and back to the heart, which is called pulmonary circulation, and the other throughout the rest of the body and its organs including the brain (systemic circulation).
most mammals, have closed cardiovascular systems. The two main circulation pathways in invertebrates are the single and double circulation pathways.
Answer:
chlorophyll
Explanation:
Chlorophyll gives the algae their green color.
According to the CDC, tooth decay
affects more than one-fourth of U.S. children aged 2 to 5.Tooth decay is the
damage of the structure of the tooth which is caused by acids that are produced
when sugar is being broken down by plaque bacteria in the mouth. Tooth decay is the primary cause of tooth loss in children in the United
States.
Answer:
The chemical level of organization is the simplest level. It includes the building blocks that make life possible. Atoms bind together in various combinations to form molecules that take up several essential functions of life.
Explanation: Hope this helps can I please have brainliest.