Touching a jellyfish can be a very painful experience whereas touching a comb jelly is not painful. Why is there a difference?
A. Ctenophores only use nematocycts for feeding, not for defense.
B. Ctenphores do not possess nematocysts.
C. Nematocysts in ctenophores lack venom.
D. Ctenophores have very reduced nematocysts that cannot penetrate human skin.
Answer: B
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Many species of ants "farm" aphids, protecting them from predation and collecting concentrated sugars (i.e. honeydew) from them. This type of ant/aphid relationship is known as
A. dispersive mutualism. B. defensive mutualism. C. parasitism. D. trophic mutualism. E. commensalism.
Which of the following is NOT involved in
periodontitis? a. aerobic bacteria b. Streptococcus mutans c. a host of bacterial fermenters d. organic acids e. inflammation
When an allele's effect on a trait is masked by that of an allele paired with it, the second allele is
referred to as a. dominant. b. recessive. c. codominant. d. incompletely dominant. e. hybrid.
In lab, a student observes some dull, wrinkled brown colonies growing on their agar. They Gram stain the sample and observe single bacilli. Their blood agar does not reveal any hemolysis while their MSA has growth and fermentation. Using the following table and the given observations, determine which microorganism this would most likely be.Bacilli B. cereus B. subtilis Colony morphology Dull, frosted colonies Dull, wrinkled colonies cream to brown colors Microscopic arrangement Chains Single bacilli Catalase + + Blood agar Beta Gamma Mannitol salt agar - + growth and + fermentation Pseudomonas P. aeruginosa Catalase + Oxidase + Motile + Blood agar Beta Glucose fermentation + Escherichia E. coli Lactose fermentation + Motile + Citrate
fermentation - Urease - Catalase + A. E. coli B. B. subtilis C. Pseudomonas aeruginosa D. B. cereus