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.
The lungs belong to the respiratory.
A small change in a persons DNA can cause any number of mutations that may be completely harmless or fatal depending on where the mutation (change) occurs in ones DNA.
Within any ecosystem, there is a fixed amount of energy available for
organisms to use. since organisms usually produce more offspring than a
given
ecosystem can support, this causes competition. They compete over who will be the dominant one and who will be left to die.
