Pesticides is it a pure substance or a mixture

Which statement is best described as a atom

Adeuteron, 21h, is the nucleus of a hydrogen isotope and consists of one proton and one neutron. the plasma of deuterons in a nuclear fusion reactor must be heated to about 3.02×108 k . what is the rms speed of the deuterons? express your answer using two significant figures.

Chromosome 17 is made of over million base pairs.