For oi, how is collagen transported across the cell membrane

Natural selection changes allele frequencies because some survive and reproduce more successfully than others.

How can we use spectral lines of light coming from the superclusters to identify which is receding from earth at the slowest rate.

What is the purpose of transcription? a. to copy the nucleotide in dna b. to form rna molecules from dna c. to produce a nucleic acid sequence from an amino acid sequence d. to link amino acids together to form stands of protein