Essential amino acids cannot be made by the body. As a result, they must come from food. The 9 essential amino acids are: histidine, isoleucine, leucine, lysine, methionine, phenylalanine, threonine, tryptophan, and valine.
Yes, it is. Potassium’s symbol is K. It’s atomic number 19.
A difference between plant cells and animal cells is that most animal cells are round whereas most plant cells are rectangular. Plant cells have a rigid cell wall that surrounds the cell membrane. Animal cells do not have a cell wall.
Hollow, that's why birds can fly. There is nothing in the bone to weigh them down.
