Which best explains what happens during crossing over? The chromosomes have electrical connections that allow them to line up randomly.
Paired chromosomes overlap and portions of DNA switch between chromosome.
Genetic material is switched because the chromosomes line up independently.
Chromosomes line up randomly and cross genetic information between unpaired chromosomes.

Calculate the mass percent of hydrogen in methyl acetate

1. suppose a reaction mixture, when diluted with water, afforded 300 ml of an aqueous solution of 30 g of the reaction product malononitrile [ch2(cn)2], which is to be isolated by extraction with ether. the solubility of malononitrile in ether at room temperature is 20.0 g/100 ml, and in water is 13.3 g/100 ml. what weight of malononitrile would be recovered by extraction with (a) three 100-ml portions of ether and (b) one 300-ml portion of ether? suggestion: for each extraction, let x equal the weight extracted into the ether layer. in part (a), the concentration in the ether layer is x/100 and in the water layer is (30 x)/300; the ratio of these quantities is equal to k 20/13.3.

Why is the melting of ice a physical change ?