Which of the following describes vessels critical to fetal circulation but does not play a role in adult circulation

a) aorta
b) pulmonary artery
c) inferior vena cava
d) ductus arteriosus

Which are forms of nitrogen that are usable by humans

When analyzing tree rings, what do scientists assume a thin ring indicates?

2. how does the miller-urey experiment fall short of demonstrating that life can arise from inorganic molecules? explain. a. it doesn't show a leap between a collection of amino acids and a single-celled organism. b. it recreates the conditions that existed at the earth's beginning, but no molecules form as a result. c. it doesn't provide evidence of the formation of amino acids. d. it doesn't show how multicellular organisms developed from unicellular organisms