There are two classes of membrane transport proteins—carriers<span> and </span>channels<span>. Both form continuous </span>protein<span> pathways across the lipid bilayer. Whereas transport by </span>carriers<span> can be either active or passive, solute flow through </span>channel proteins<span> is always passive.</span>
Answer: E- The right ventricle.
Explanation: Deoxygenated blood with carbon dioxide and metabolic products collected from the tissues by the capillaries returns to the heart via the venous system and enters the right atrium of the heart. It is then pumped to the right ventricle, then transported to the lungs via the pulmonary artery for gaseous exchange, where oxygen is collected and carbon dioxide is dropped off.
Answer:
D. They define geological periods because scientists use them as reference points for tracking the history of the earth.
Explanation:
Catastrophic events related to changes in geological timeline are very useful in defining geological periods.
These events have very significant appearance in the geological record and can be used to determine the history of the earth.
The catastrophic events usually culminates into extinction cycles or termination of some organisms from the earth surface.
Geologists use these events that are often wide spread to delineate geological periods.
Valence electrons would be found in the outermost shell of atom models!
Hope this helps (:
