A constant force, F, is applied to a block sitting on a bench. There could be other forces acting on the block at the same time. In which of the following cases is no work done on the block by F?

Ithink it’s: light bounce if off a mirror

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.