During which phase of Meioses does crossing over of chromosomes occur

After fertilization, which type of cellular division is responsible for the growth and development of a complex, multicellular organism?

What are the doorways into and out of cells, attached to the membrane, and built in the rough er.

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