if you have 100 grams of a radioactive isotope, with a half life of 10 years how much of that isotope would be left after 10 years

Which element is used in photosynthesis found in atmosphere and fixed by bacteria?

Which statement best describes the relationship between an allele and a gene? question 1 a. an allele is a variation of a gene that can be expressed as a phenotype. b. an allele is the part of a gene that attaches to messenger rna molecules. c. an allele is a segment of a dna molecule that controls replication of a gene.

Plsss > .< compare and contrast the characteristics of flatworms rounds worms and earthworms