A ______ usually is the lymphoid tissue first to encounter pathogens and antigens that enter via the nose and mouth.
A. lymph node
B. tonsil
C. thymus
D. spleen
Answer: B. tonsil
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Humans cannot survive at sea by drinking salt water. However, marine vertebrates such as sea turtles and various sea birds can survive by drinking salt water. What do they have that humans do not?
A. kidneys that are extremely good at producing a concentrated urine. B. body fluid concentrations that are similar to or greater than those of seawater. C. the ability to secrete salts and wastes into their intestinal contents like an insect. D. They use ammonia as their primary nitrogenous waste. E. salt glands.
________ is the sequencing and assembly of random, overlapping cloned DNA fragments into long, contiguous sequences
Fill in the blank with correct word.
The ultracentriguge is an important piece of lab equipment frequently used by cell biologists. What are some applications for the ultracentrifuge? choose one or more
A.) determining whether prokaryotic cells are bacteria or archaea B.) separating isomers of 6-carbon sugars from each other C.) separating different cellular organelles from each other D.) determining the sequence of (linear order of) monomers in a macromolecular polymer
Mark suffers from nosebleeds and gastrointestinal bleeding due to increased breakdown of platelets outside the marrow. This is called
A. hemophilia. B. sickle-cell anemia. C. thromboembolism. D. prothrombin disease. E. thrombocytopenia.