When a tourist buys a sand dollar at a beach shop, what are they buying?
A. Anendoskeleton of calcium carbonate ossicles
B. A calcium carbonate shell secreted from the mantle
C. An endoskeleton made of cartilage
D. An endoskeleton made of bone
E. A molted exoskeleton made of chitin
Answer: A
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What were the conclusions of Gibson’s experiments with small mammal populations?
a. Fragmentation increases biodiversity. b. Fragmentation leads to extinction of native populations. c. Fragmentation does not affect small mammal populations. d. Fragmentation has the same effect on large and small mammal populations. e. Fragmentation has more impact in aquatic than in terrestrial habitats.
I've cloned a genomic library and know that my bacteria have foreign DNA fragments inserted into the
cloning vector. I now need to identify the specific bacteria that have the gene coding for protein X. How can I locate these bacteria?
a. DNA hybridization of the different colonies b. PCR of the same bacterial mixture that was spread on agarose plates c. restriction endonuclease treatment of DNA from some of the bacterial colonies d. agarose gel electrophoresis of DNA isolated from the bacterial colonies e. transfer the bacterial colonies to filter paper
Which of the following statements is false?
a. Only B cells and their progeny make antibodies. b. The primary immune response is faster and more complete than a secondary immune response. c. Naive B cells already have antibodies but have not yet encountered an antigen. d. Macrophages will digest invading bacterial cells but do not destroy the antigens that eventually become mounted on their surfaces. e. B cell progeny may differentiate into memory cells.
An ecologically friendly city that has housing, work, and schools located close to each other would decrease the requirement for
a. public transportation b. pedestrian traffic c. bikes d. cars e. electricity