Fiddler crabs are invertebrates. That means they do not have a backbone (that's made out of vertebrae). Does this mean they don't have a skeleton?

The galapagos island contain 13 species of finches four of the species are seen here it is believed that all of the species had one common ancestor and overtime

Which statement describes john tuzo wilson’s contribution to the theory of plate tectonics?

A60-tooth gear is connected to a 72-tooth gear. if the smaller gear turns 12 times, how many turns does the larger gear make?