the sears tower is 443 m rall. Mr tessmer wants to set the world's stair climbing record and runs all the way up to the roof of the tower in 15.0 min. On the way down, he is so tired that it takes him twice as long to descend. what is Mr tessmers average speed (in m/s) during the entire trip?

Answerthe valence of an element or radical is equal to the number of positive or negative charges on the ion.

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?   answer :   the genome of the endosymbiont is more closely related to members of the group in which it originally evolved, while the nuclear genome of the engulfing organism has its own evolutionary trajectory.