Which of the best explanation of directional natural selection occur by change in environmental condition?

A. Increase in the frequency of dark-colored mutants in polluted areas, became known as industrial melanism

B. Numerous insect pests become resistant to insecticides and numerous bacteria become resistant to antibiotics.

C. A plant that is too short may not be able to compete with other plants for sunlight. However, extremely tall plants may be more susceptible to wind damage

D- Beetles move into a new environment with patches of light-green moss and dark-green shrubs, both light and dark beetles might be better hidden (and survive better) than medium-green beetles

#Question id: 31385

#Unit 4. Cell Communication and Cell Signaling

#Question id: 5659

#Unit 5. Developmental Biology

 Following are the statements related to mammalian chaemotaxis .
A. During chaemotaxis, the oocyte and its accompanying cumulus cells secrete molecules that attract only uncapacitated sperm toward the egg during the last stages of sperm migration.
B. These chaemotactic compound are hormone progesterone, which is made by the cumulus cells.
C. Progesterone has been shown to bind to a receptor that activates Ca2+ channels in the cell membrane of the sperm tail, leading to sperm hyperactivity and provides directional cue.
D. Cumulus cells also secrete a substance, CRISP1, that attracts sperm and hyperactivates them through CatSper channels similar as in sea urchins.
Which of  the following statement is incorrect?

#Question id: 3781

#Unit 3. Fundamental Processes

Hershey and Chase used a DNA-based virus for their work. How might the results have been different if they had used an RNA virus?

#Question id: 10652

#Unit 10. Ecological Principles

Which factors (limited space or overcrowding; limited food; Predators; parasite and diseased) tend to act in a density-dependent manner; Tony Sinclair (1989) many studies of density dependence in 51 populations of insects, 82 populations of large mammals, and 36 populations of small mammals and birds. Which of the following observation is most likely true?

a) Insects showed a wide variety of causes of density dependence and no one density-dependent factor was of overriding importance

b) The lesser the amount of available food, the greater the mortality of large mammals

c) Space and social interactions were more important for smaller mammals and birds, because they are more territorial

#Question id: 4480

#Unit 3. Fundamental Processes

The reason for TBP’s unorthodox recognition mechanism is