Quick! i've been stuck on this one for < 3

What is the answer for the complicated molecules that make up living things usually contain carbon. why is carbon so important in these molecules?

Of seawater increases with decrease in the temperature. therefore, the cold water sinks to the deeper layers at the bottom

Atest cross can be used to -predict the phenotypes of a monohybrid cross -predict an unknown genotype of a purebred dominant plant -cross-breed dominant and recessive plants -give probabilities that a trait will appear