Aunifying concept that forms the basis of scientific investigation in a particular field is called a(n)

a. possible errors

d. new questions

explanation:

predictions and planning happen before. a summery comes after. errors you get after investigation and new questions propose what you can look for in the future.

the second type of galaxy is called a barred spiral, which has a thing called a bar straddling the nucleus

compost can be added to topsoil as a:

pesticide

nucleic acid molecules are incredibly complex, containing the code that guarantees the four different nucleotide units comprise dna, the nucleic acid of interest to the genealogist. and one of four nitrogen-containing molecules called nucleotides