Why was earth and other planets not solid when they formed during the precambrian approx 4600 million years ago?

Ascientist and her team counted 200 individual deer in an area of 10 square kilometers. what is the population density?

And give a detailed description! scientist observes the boundary between two tectonic plates for a decade and finds that no new volcanoes have formed over the course of her investigation. does this result support the theory of plate tectonics? why or why not?

Transmission electron microscope are best for viewing a) microorganisms in pond water b) internal organs of a mouse c)internal structures of a cell d) surface features of a specimen