Over the past 60 years, the level of carbon dioxide in the atmosphere has been continually increasing. many scientists hypothesize that this increase has led to an imbalance in the carbon cycle and a climatic trend known as global warming.

an organism's phenotype is the  form of a trait  that it  displays. for  flowercolor, a pea  plant  can  display  a phenotype of purple or white flowers. an organism's  genotype  is the alleles of a gene it contains. based on his data, mendel concluded that a phenotype can be  determined  by more than one  genotype.