All life on Earth, at heart use a membrane that separates their organism from its environment. For it to stay alive, the organism takes in important materials for making energy, while also shuttling out toxic substances such as waste products. In this regard, water is essential simply because it's a liquid at Earth-like temperatures.
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Answer:
because people where not alive yet oontill cenoznic era
Explanation:
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.
<span>Transpiration is considered as necessary evil because during CO2 and other gaseous exchange, water also escapes and that could be harmful to the plant.</span>
