Answer:
B is the answer
B. Improved living conditions resulted in a decline in the mortality
rate.
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Answer:
it would be C, D, E
A is a mixture
B is a mixture
C is a pure substance because Oxygen gas by the chemical symbol O2, is strictly pure
D is pure substance because Gold is one of the basic elements found naturally in nature, and as such, in its pure form
E is a pure substance because Both ice and liquid water are the same substance. H2O Though ice water is a mixture of both solid and liquid it is a pure substance, based on the molecular structure of its components .
F is a mixture
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Stomata are tiny pores present in the leaf that allows gas exchange and is where water vapour leaves plants and carbon dioxide enters. Special cells called guard cells present in the stomata, control each pore's opening or closing. When stomata are open, transpiration rates increase; when they are closed, transpiration rates decrease.