Biology helping with medical research and treatment
For the answer to the question above, I think that <span>Mendeleev's eka-aluminum is what we know today as <u><em>GALLIUM</em></u></span><u><em>.</em></u>
or the era of Mendeleev is <u><em>Aluminum</em></u> which is that <span>it would <u><em>be a soft metal with a low melting point.</em></u></span>
I hope my answer helped you. Have a nice day!
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- Oxygen cycle is the cycle which maintains the level of oxygen in the atmosphere.
- Oxygen from the atmosphere is used up during combustion, respiration and in the formation of oxides of nitrogen.
- This oxygen is returned to the atmosphere by lithosphere.
- This forms the oxygen cycle in nature.
Hope you could get an idea from here.
Doubt clarification - use comment section.
The answer is 2 because they are renewable which means replaceable