Let "r" stand for the recessive red hair trait. A person with red hair must have a genotype of "rr" ( one from each parent) in order to have red hair( red hair being the phenotype).
Let "B" stand for brown hair and "b" stand for not brown hair. A person with brown hair can have a genotype of "Bb" or "BB" and have a phenotype of Brown hair. This is becasue brown hair "B" is the dominant trait.
Answer:
We hear a lot about the amount of carbon in our atmosphere increasing, but the actual number of carbon atoms on our planet has not changed since the Earth first formed. It's just that more carbon is spending more time as gas.
Explanation:
Sample A has a much stronger melting point and it will last longer than Sample B.