Which happens during crossing over? Two sex cells join together and combine DNA.
Genes are exchanged between two alleles.
Genes are exchanged between two egg cells.
Chromosomes line up randomly during metaphase I.

What are the first three quantum numbers for the electrons located in subshell 2s?

Oil rich countries in the middle east cover about 4% of earths total land area but prossess about 48% of the worlds known oil reserves what is the main reason for high concentration of reserves in this part of the world

What type of electromagnetic waves does the human eye see as the colors red blue or green a visible light waves b radio waves c infrared waves d microwaves