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TLS Online TPP Program

#Question id: 14825

Actinomycetes characteristically form long multinucleate filaments or hyphae that may branch to produce a network called a 

#Unit 2. Cellular Organization
  1. Filament
  2. Conidia
  3. Mycelium
  4. Thallus
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TLS Online TPP Program

#Question id: 12806

#Unit 10. Ecological Principles

Which  of  the  following  areas  of  study  focuses  on  the  exchange  of  energy,  organisms,  and  materials  between ecosystems?
TLS Online TPP Program

#Question id: 12807

#Unit 10. Ecological Principles

If Earth's axis of rotation suddenly became perpendicular to the plane of its orbit, the most predictable effect would be
TLS Online TPP Program

#Question id: 12808

#Unit 10. Ecological Principles

When climbing a mountain, we can observe transitions in biological communities that are analogous to the changes
TLS Online TPP Program

#Question id: 12956

#Unit 10. Ecological Principles

For  nearly 200  years, biogeographers have  noted that  the  tropics  have  more terrestrial species than  temperate regions. Which of the following is NOT a plausible explanation for this pattern?
TLS Online TPP Program

#Question id: 12957

#Unit 10. Ecological Principles

Dichlorodiphenyltrichloroethane is related to the phenomenon of:
TLS Online TPP Program

#Question id: 12958

#Unit 10. Ecological Principles

The Norway rat (Rattus Norvegicus), a widespread pest, was controlled for about a decade by the anticoagulant warfarin. This chemical substance, placed in food pellets, is absorbed by the intestinal tract and inhibits the clotting of blood. After a population decline for about 10 years, rat populations increased and stabilized. In one European population, as illustrated in the graph below, the percentage of rats resistant to warfarin has remained fairly stable over a number of years

Resistance to warfarin is governed by a dominant autosomal gene, R. More than 15 percent of the resistant animals are heterozygous at this locus (Rr). The table below indicates the response to warfarin and relative reproductive fitness of individuals that are homozygous or heterozygous for the dominant gene (R). The RR individuals have a 20-fold increase in vitamin K requirement over individuals.


Fitness is a measure of the reproductive success of a particular genotype. The highest fitness is 1.00.

The strong dependence of RR individuals on large quantities of vitamin K probably is responsible for