During week 7, what new bacteria was introduced to Patient 23's microbiome after he was treated with antibiotics? 1. c. difficile
2. salmonella
3. bacilli
5. Actinobacteria

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

in 1859, charles darwin set out his theory of evolution by natural selection as an explanation for adaptation and speciation. he defined natural selection as the "principle by which each slight variation [of a trait], if useful, is preserved".

igneous rocks which formed by the crystallization of magma at the surface of the earth called extrusive rocks. they are characterized by fine-grained textures because the rapid cooling at or near the surface did not provide enough time for large crystals to grow.