Paper burns by combining with oxygen. why doesnt paper burn every time it contacts oxygen

Why are some people more concerned about shark survival than about shark attacks?

What are the four stages of cell signaling?

Some steps in cell division are shown below: 1. chromosomes condense and pair up 2. segments of dna of sister chromatids twist and cross 3. exchange of dna occurs between chromosomes 4. four daughter cells are created that are haploid which of the following steps is least likely to occur during meiosis 1?