Which of the following is not a blood cell? a. leukocyte
b. lymphocyte
c. erythrocyte
d. monocyte

What links the two strands in a dna helix together in the middle? a. phosphate groups b. sugar rings bonded together c. proteins d. bases with hydrogen bonds

In general, characteristics that an organism survive and reproduce become more common over time. what mechanism of evolution causes this?

Describe the two types of vascular tissue