Pulmonary surfactant is a mixture of lipids and proteins which is secreted into the alveolar space by epithelial type II cells. The main function of the surfactant is to lower the surface tension at the ir/liquid interface within the alveoli of the lung. In babies born prematurely, pulmonary surfactant may not be present in adequate amounts due to insufficient exocytosis in type II alveolar cells.
The correct choice is B. The enzyme binds to the substrate. The other choices are incorrect.
Answer:
-300 N
Explanation:
The key words here are "constant speed". By this, we mean that all the forces on the object (the sailing boat here) are balanced - so they must be equal in magnitude.
Here, we know that the boat has a forward force of 300 N. Because the forces are balanced, then the backward force must also have a force with magnitude 300 N.
However, note that because the backward force is in the opposite direction as the forward force, we must put a negative sign on the 300. So our answer is: -300 N.
