What is the basic unit of the dna molecule?

nucleotides

Explanation: Nucleotides are building blocks or monomeric units of nucleic acids. DNA is deoxyribonucleic acid. DNA is made up of three parts: A nitrogenous base, a deoxyribose sugar and a phosphate group. A molecule containing a deoxyribose sugar, a nitrogenous base and a phosphate group is called a nucleotide. Nucleotides are joined together by a phosphodiester bond to form polymers known as nucleic acid.

chlorophyll a: this is the most abundant pigment in plants. chlorophyll a absorbs light with wavelengths of 430nm(blue) and 662nm(red). it reflects green light strongly so it appears green to us.

burning of wood and coal

explanation:

the panel also concluded there's a better than 95 percent probability that human-produced greenhouse gases such as carbon dioxide, methane and nitrous oxide have caused much of the observed increase in earth's temperatures over the past 50 years.