<span>Unidirectional flow in the heart is ensured because the heart contains valves that prevent backflow.
These valves keep the flow of the heart going in one direction (hence the name "unidirectional").</span>
Adenine, thymine, guanine, and cytosine
The correct answers are a, c, d.
There are three types of capillaries: continuous, sinusoidal (or discontinuous) and fenestrated. Continuous capillaries are the most common type and they form tight junctions. Sinusoidal capillaries form an incomplete lining with several gaps, which allow red and white blood cells and some serum proteins to pass. These capillaries are mainly found in the bone marrow, lymph nodes and adrenal glands. Finally, fenestrated capillaries facilitate the movement of smaller molecules and plasma proteins and are mainly found in the small intestine. The majority of the fluid transport happens through the fenestrated capillaries.
Structurally, plant and animal cells are very similar because they are both eukaryotic cells. They both contain membrane-bound organelles such as the nucleus, mitochondria, endoplasmic reticulum, golgi apparatus, lysosomes, and peroxisomes. Both also contain similar membranes, cytosol, and cytoskeletal elements.
The skin of a cell
molecule flow from high to low
glucose facilitation
ion channels
