The oldest fossils are about ________ billion years old.
A. 1.8
B. 3.5
C. 13
D. 0.5
B. 3.5
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When a mutation disrupts or stops synthesis of a one of the globin chains of hemoglobin, the resulting disorder is called ________
a. iron-deficiency anemia b. beta-thalassemia c. polycythemia d. leukemia
Horsehair worms, in the phylum Nematomorpha, do not have a respiratory system. They are usually found in puddles of water or on damp sidewalks and patios, or they may come wiggling out of insects
These creatures have no economic importance other than being parasitic to some insects. Based on this scenario, horsehair worms are most likely to A) have a large surface area compared with their volume. B) be unable to efficiently digest food. C) use large amounts of energy. D) have very thick bodies. E) have a dry skin surface.
Which of the following is not a lymphatic organ?
A. red bone marrow B. tonsil C. liver D. thymus E. spleen
What argument do scientists who support the metabolism-first model use to dispute the replicator-first model?
A) RNA can only be used to make proteins, not other nucleic acids. B) The replicator nucleic acid molecule would be too large and complex. C) Replicators cannot exist without metabolism. D) DNA cannot replicate without the help of proteins.