Need help please didn’t get it

The phylogenetic tree illustrates the relationship between humans and our closest living relatives. the tree was based on biochemical comparisons, including dna and amino acid sequences. according to the biomolecular data, we could infer that

Genetic disorders can result when sister chromatids fail to seperate properly. during what phase is this problem most likely to occur?

Omg substrates with the same size and shape as the active site will bind to the enzyme. why is the key labeled the “bad” substrate?