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.

Ase your answer to this question on the information below.hydrocarbons and fissionable nuclei are among the sources used for the production of energy in the united states. a chemical reaction produces much less energy than a nuclear reaction per mole of reactant.the balanced chemical equation below represents the reaction of one molecule of a hydrocarbon with two molecules of oxygen.chemical equation: ch4 + 2o2 → co2 + 2h2o + 1.48 × 10−18 jthe nuclear equation below represents one of the many possible reactions for one fissionable nucleus. in this equation, x represents a missing product.nuclear equation: write an isotopic notation for the missing product represented by x in the nuclear equation.

Why is nh3 classified as a polar molecule

Consider a culture medium on which only gram-positive organisms such as staphylococcus aureus colonies can grow due to an elevated nacl level. a yellow halo surrounds the growth, indicating the bacterium fermented a sugar in the medium, decreasing the ph as a result and changing the color of a ph indicator chemical. this type of medium would be referred to as a differential and enrichment culture.