Asingle celled organism can be classified as a prokaryote based on the absence of

Nucleus

Explanation:

Prokaryotes are the singled cell organisms that do not have a true nucleus which means like eukaryotes they lack a membrane-bound nucleus. So the genetic material of prokaryote are present in the cytoplasm of their cell.

Apart from the nucleus prokaryotes also lack membrane-bound organelle like mitochondria or chloroplast which are present in eukaryotes and helps in ATP formation for the cell. So prokaryotes use the plasma membrane of cell for production of ATP.

Therefore an organism can be classified as a prokaryote if it lacks a nucleus and other membrane-bound organelles.

when a reversible reaction is occurring in both directions at the same rate; the products and reactants do not change in concentration. a chemical reaction where the compound is broken into its constituent parts.

lizards have adapted to life in the desert. some desert lizards have toes with spiny scales to them run across the sand without sinking. some use the sand to hide from predators, or to search for small animals that they prey upon.