Asugar, a phosphate group, and a nitrogen base form the building blocks of which organic compound? a. carbohydrates b. lipids c. nucleic acids d. proteins

Match the types of competition to their descriptions.

How can a geological time scale best be reconstructed? a) comparing vestigial structures in living species b) comparing homologous structures in living species c) examining homologous structures in fossil remains d) examining the written records of scientists from past cultures

Number and variety of living organisms includes genetic, species, and ecological types