Answer:
Active transport requires cellular energy for substances to cross the cell membrane; passive transport does not.
Explanation:
Active Transport works against the concentration gradient and therefore needs energy to make it happen
Passive transport such as Diffusion and Osmosis uses the properties of natural movement of particles which moves the molecules from areas of high concentration to areas of low concentration or down the concentration gradient and happens passively without the need for energy
Answer:
The Greeks believed in the geocentric model of the universe.
According to this model, the Earth was present in the center whereas the Sun, moon, other planets etc revolved around it. According to Plato, the Earth was spherical in shape and it did not move. Greek philosophers, such as Aristotle and Plato, believed the Earth to be the center of the universe. All other heavenly bodies orbited around the Earth according to the Greek philosophers.
Answer:
A. INACTIVE PRECURSOR OF THE ENZYME PEPSIN THAT DIGESTS PROTEINS IN THE STOMACH.
Explanation:
Pepsinogen is the inactive precursor of pepsin produced by the chief cells of the stomach lining. The stomach walls are lined by majorly two types of cells; the chief and the parietal cells. Chief cells secretes pepisinogen and parietal cells secrete hydrochloric acid in the stomach lining. The chief cells upon the signals of increased protein substance in the stomach produces pepsinogen which upon it release, it is activated to the active enzyme Pepsin by the hydrochloric acid from the parietal cell. Hydrochloric acid provides the acidic environment needed for the action of pepsin in the stomach. The pepsin begins the digestion of proteins into small amino acids in the stomach,
There are different types of channels for blood flow that transport the blood pumped by the heart. They greatly differ only in the size of their diameters. Arteries are the big ones that are located mostly near the heart. Veins are the next which is where nurses inject you to gather blood. Then, the smallest ones are the capillaries.
