Crossing over occurs at the four-strand stage when two homologous chromosomes, each consisting of a pair of sister chromatids, are paired. Each crossover involves just two of the four strands and generates two recombinant strands.
Hope this helps!
The main function of the mitochondria is respiration in the cell. To produce energy from broken down organic molecules. (i.e. carbohydrates.)
In comparison to eukaryotes, prokaryotes are smaller. Eukaryotes and prokaryotes<span> are type of cells. The prokaryotes </span><span> contain no membrane-bound organelle such as</span><span> nucleus and are found in the domains of Bacteria and Archaea. E</span>ukaryotes contain a nucleus and make up the remaining domain. Prokaryotes tend to be much smaller in size than eukaryotic cells.