The answer the question would be six
Cells<span> are the simplest structures to fit all of the characteristics necessary to be </span>considered<span> alive.</span>
Earthworms have two muscles which is used in locomotion. Both muscles are circular and longitudinal (inner layer of the series of muscles). The diameter of the earthworms body is reduced when the circular muscles are contracted which makes them appear to be thin. The worm appears short when the longitudinal muscles contract thus, its length is reduced.
Amphioxus on the other hand, have two unique muscle fiber types. This includes deep fibers and smaller but mitochondria-rich superficial fibers. E<span>ach of which has its own innervation.</span>
Hmm good question. Well I would have to test it for where there are no living life. I would have to build another NASA in the County because there is plenty of room there. Mars is made out of Dusty Crust that is about 30 miles thick. And let's say that the desert's Dusty Crust is about 5 miles - 15 miles thick. That will give about the same amount of surface that mars has. So we would know what to build for a perfect lander to work on Mars. This isn't much but it is something.