What holds the two strands of dna molecules to each other

The scales shown in the introduction measure mass, or the amount of matter in a particular object. the scientific law of conservation of mass states that matter cannot be created or destroyed during a chemical reaction, but it can change from one form to another. did the simulation support this scientific law? explain why or why not.

In a village where the proportion of individuals who are susceptible to malaria is .70 and population is at hardy-weinberg equilibrium what population is heterozygous hba/hbs

"does stress during a woman's first trimester of a pregnancy affect the infant's birth weight? " is a