Why is the big bang a theory and not a fact?

because no one is able to witness it
because there are no theories that could be possible.
because theories never turn into facts.
because there are no such things as facts.

The model illustrates a process by which a substance is taken up by a cell

The idea that all living things are made up of cells is considered scientific law. this means the idea is an emerging scientific idea that has a logical explanation. has been tested with similar results at least twice. is supported by scientific consensus and a large amount of evidence. has been rejected only once by the scientific community

Which of the following graphs have the same wavelengths