A researcher studying bacterial toxin predicts that a lysine within the toxin is important for binding it’s target cell.  She used site-directed mutagenesis to change a codon for lysine (AAA) to one for asparagine (AAU).  However, the mutant toxin still binds to its target cell just as well as the wild-type toxin bound and appears to have no other changes. This type of mutation is probably

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#Question id: 12756

#Unit 10. Ecological Principles

Flycatcher birds that migrate from Africa to Europe feed their nestlings mostly with moth caterpillars. The data presented show the mean dates of egg laying, hatching, and fledging of flycatcher young, and the 1980 and 2000 peak mass of caterpillars.

The most likely cause for the shift in caterpillar peak mass is

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#Question id: 11403

#Unit 10. Ecological Principles

Several categories of risk of species extinction have been defined. A species can be determined as critical endangered if there is considered to be

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#Question id: 12328

#Unit 10. Ecological Principles

The dominant species in a community is

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#Question id: 19278

#Unit 9. Diversity of Life Forms

which of these statements is true of the pine life cycle? 

TLS Online TPP Program

#Question id: 2063

#Unit 2. Cellular Organization

In what way do the membranes of a eukaryotic cell vary?