Gravitational.....................
Epithelia are classified by the number of cell layers and the general shape of the cells
The human brain consumes up to 20% of the energy used the entire human body which is any other single organ. the brain represents inly 2%of the body wheight yet it recieves 15% of the cardiac output and 20% of the total body oxygen consumption.
The answer is the apoplast, the symplast, and the transmembrane pathway.
1. The apoplast pathway occurs through cell walls and space between cells. So, water does not cross any cell membrane as it travels this pathway.
2. The symplast pathway occurs through the continuum of cytoplasm. So, water travels through plasmodesmata which connect cells.
3. The transmembrane pathway occurs across cell membranes. So, water enters the cell on one side of the membrane and exits on the other.
