A car travels 40 miles north in 30 minutes and then turns around and travels 20 miles south in 30 minutes. What is the cars average speed in miles/hour?

Shy diving is the only sport which doesnot require a high level of physical fitness

Simple, don't do it. just don't go to that dock

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.