Certain preparations contain killed or weakened live biological agents that, upon injection into our body, protect the body against those pathogens. what are these preparations called?

b. the carbon cycle ensures living things have a source of hydrogen

i think it is dna, i'm not totally sure but i think it might be.

an organism's phenotype is the  form of a trait  that it  displays. for  flowercolor, a pea  plant  can  display  a phenotype of purple or white flowers. an organism's  genotype  is the alleles of a gene it contains. based on his data, mendel concluded that a phenotype can be  determined  by more than one  genotype.