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TLS Online TPP Program

#Question id: 9233

What is the biggest problem with selecting a site for a reserve?

#Unit 9. Diversity of Life Forms
  1. Making a proper selection is difficult because currently the environmental conditions of almost any site can change quickly.
  2. Keystone species are difficult to identify in potential reserve sites.
  3. Only lands that are not useful to human activities are available for reserves.
  4. Most of the best sites are inaccessible by land transportation, so making roads to them is often prohibitively expensive.
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TLS Online TPP Program

#Question id: 12238

#Unit 10. Ecological Principles

The mussel Mytilus edulis thrives in saline habitats, in both the highly salty seawater of tidal zones and the less salty estuaries. This results in two kinds of populations: one adapted to the higher salt concentrations of the tidal zone, and one adapted to the lower salt concentrations of the estuary. It has been found that the more salt-tolerant populations have high frequencies of an allele that produces an enzyme involved in maintaining osmotic equilibrium. Conversely, estuarine mussels having the same enzyme seem to be disfavoured and have a much higher death rate than mussels without the allele. Adult estuarine populations do have lower frequencies of this allele. Each spring, large numbers of larvae from  the salty habitats pour into the estuaries.
The invasion of the seawater larvae would be expected to facilitate change in the genetic structure of the estuarine population by a process called
TLS Online TPP Program

#Question id: 5658

#Unit 5. Developmental Biology

 Following events occur during fertilization in mammals.

A. sperm penetrates cumulus layer

B. sperm nucleus delivered into cytoplasm

C. sperm plasma membrane fuses with egg plasma membrane

D. calcium waves

E. enzymes released from acrosome on sperm head enable sperm to penetrate zona pellucida

F. transit through the cumulus or binding to zona pellucida elicits acrosomal reaction in sperm

G. egg completes meiosis and development is initiated

which of the following sequence is correct?
TLS Online TPP Program

#Question id: 9608

#Unit 9. Diversity of Life Forms

Darwin analogized the effects of evolution as the above-ground portion of a many-branched tree, with extant species being the tips of the twigs. The common ancestor of two species is most analogous to which anatomical tree part?
TLS Online TPP Program

#Question id: 9244

#Unit 9. Diversity of Life Forms

One characteristic that distinguishes a population in an extinction vortex from most other populations is that
TLS Online TPP Program

#Question id: 4665

#Unit 3. Fundamental Processes

Mode of activation of rifampicin in E.coli is through