Chloroplasts. They are only in green plant cells, so, unless you are a green plant, humans and flatworms would not contain them.
A. the population of higher trophic levels is greater than lower trophic levels
The answer to this question would be: <span>proceed through the trachea, bronchi, and then bronchioles.
After going pass the oropharynx the air will be going to trachea, </span>bronchi, bronchioles and will end in the alveolus. In alveolus, the oxygen from the air will diffuse to the blood while carbon dioxide will diffuse to the alveolus. The carbon dioxide is going out of the lungs when doing expiration.
<span>The genetic term used to describe an observable trait is phenotype. More specifically phenotype is the set of observable characteristics of an individual resulting from the interaction of its genotype with the environment.</span>
