How is it possible that phylogenies based on sequences from nuclear genomes and organellar genomes (i. e., chloroplasts and mitochondria) from the same group of species yield phylogenetic trees with different branching orders?

From the sequence, we can only tell the percentage similarity between the genome sequences, however, the ambiguity arises from the various sequences of possible modifications in the genomic sequences. For example in a conserved genomic seqence CAGGGCCC, some organisms have this sequence and other organisms have the sequence CAGGACCC, In this case, it is fairly straightforward to say that the latter group evolved from the former group with a modification in the G base to A base. Similarly if another group arises with the sequence CAGGACTC, it is also probable to say that this group arised from the CAGGACTC group with an additional modification.

However, who's to say that the CAGGACTC group did not evolve first and the mutation from C to T base evolved later. If so, then the order of branches on the tree would change. This is just one example of the ambiguity that can arise from determining the order of genomic sequences mutation to determine the order of evolution.

what statement best describes the difference between the sympathetic and parasympathetic nervous systems?

the sympathetic nervous system prepares the body for intense physical activity and is often referred to as the fight-or-flight response. the parasympathetic nervous system has almost the exact opposite effect and relaxes the body and inhibits or slows many high energy functions.

prophase is the first step in mitosis and will show one huge circle (nucleus) and centrioles - nothing is being done to it. metaphase is the third step and where the chromatids meet in the middle and the centrioles are at opposite ends. anaphase is the fourth step and where the chromatids start to split/separate. telophase is the second to last step where the chromatids start to split along with the centrioles, it looks like there is getting ready to be two different cells. if you follow this, then it should you to answer what it looks like. have a great day and i hope i you! if i did not answer your question or you are confused, let me know and i will you as much as i can.