Rain forests cover just 6 percent of the earth’s land surface, yet they contain percent of earth’s species.

If the coding part of an mrna molecule is 1800 nucleotides (bases) in length, this molecule will contain codons and code for a polypeptide that is amino acids long.

Spring tides, when the high tides are at their highest and low tides at their lowest. what is it about these positions that causes these high and low tides?

In the 1500s, an astronomer developed a new model of the universe. this model had the sun at the center of the universe, not earth. who was this astronomer?