What type of blood vessel returns blood to the heart?
a. artery
b. vein
c. capillary
d. none of the above

During dna replication,each strand of dna is used as a template to produce a complementary strand of dna. this process is shown below. which base will attach to location

Under which of the following circumstances would natural selection not operate on an organism

Part a - which gene to compare? in this exercise, you will use the cytochrome c oxidase i (coi) gene to investigate relationships among salmon species. (this gene encodes a protein that functions in the mitochondrial electron transport chain.) you will compare the coi gene sequences from your salmon test samples to the standard sequences for each salmon species. in order for the coi gene to be useful for distinguishing among the different salmon species, which three statements must be true?