Naturally occurring lithium<span> (chemical symbol Li) (relative </span>atomic mass<span>: 6.941(2)) is composed of two stable </span>isotopes<span>, </span>lithium-6<span> and </span>lithium<span>-7, with the latter being far </span>more<span> ... </span>Lithium-4 contains threeprotons<span> and one </span>neutron<span>. ... An accurate </span>atomic mass<span> for </span>samples<span> of </span>lithium<span> cannot be measured for all sources of </span>lithium<span>.</span>
The root tip allows the plant to grow deeper into the soil
