b)1 unicellular- means one cell
The alkali metals in group l of the periodic table all have a single electron in the outermost shell. These metals form covalent bonds with for example the halogens, which have 7 electrons in their outer shell.
When the alkali metal halide, such as KCl is dissolved in water, it dissociates into ions. The K atom loses the single electron, and therefore has a positive charge. In turn, the chloride atom gains the electron and becomes the negatively charged chloride ion.
I think the correct term would be carbon dioxide. When a person removes co2 from the lungs by exhaling, the person also removes carbon dioxide from the blood. As the blood flows in the lungs, carbon dioxide would pass out from the blood and by diffusion to the alveoli. Then, by exhaling it is removed from the the lungs.
