When are sister chromatids separated during the cell cycle

Areal dna molecule consists of thousands of these pairs of nucleotides. what is the pairing arrangement of the nitrogen bases

What is the difference between a scientific hypotheses and a scientific theory?

According to theories of how life began, how did early organic molecules begin to separate from the outside world? a: specialized enzymes were required b: chains of amino acids created a barrier c: formation of microspheres or vesicles d: rna catalyzed the formation of membranes