What is the definition of development?

Seed plants that lived during the carboniferous impact life on earth today because a. they are the ancestors of all plant life on earth. b. their remains formed coal, which is an important resource. c. they produced fossils that are used to date many geologic events. d. their presence caused oxygen levels to drop, allowing animals to evolve.

Simple astronomical telescope the objective lens has a focal length of 75 cm and that of a piece of 5cm of the lenses are 18 cm apart when will be final image of a distant object before

What are mountains that divide european russia from asian russia?