Theorize how you would determine if a cell is an osteoblast or an osteoclast

What causes temperature extremes in the desert

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.

How does secondary succession differ from primary succession?