Phytochrome interacting factors (PIFs) act as negative regulators of photomorphogenesis such as;

a) Most PIFs are constitutive activators of genes that are expressed in the dark or in response to shade

b) Most PIFs are constitutive repressor of genes that are expressed in the dark or in response to shade

c) In the light, Pfr promotes the degradation of the PIFs, blocking the transcription of skotomorphogenesis genes

d) In the light, Pfr promotes the activation of the PIFs, blocking the transcription of skotomorphogenesis genes

Which of the following combinations is correct about PIFs?

#Question id: 11328

#Unit 10. Ecological Principles

The __________ zone is the shallow area around the edge of a lake or pond with rooted vegetation, such as water lilies and pickerelweed.

#Question id: 11329

#Unit 10. Ecological Principles

Which of the following aquatic systems is like a tropical rain forest because of its richness of biological production and diversity of inhabitants?

#Question id: 11330

#Unit 10. Ecological Principles

Bio geographers have noted that the tropics have more terrestrial species than temperate regions. Which of the following is NOT a plausible explanation for this pattern?

#Question id: 11331

#Unit 10. Ecological Principles

Based on the intermediate disturbance hypothesis, a community’s species diversity is increased by

#Question id: 11332

#Unit 10. Ecological Principles

The most plausible hypothesis to explain why species richness is higher in tropical than in temperate regions is that

 A) tropical communities are older.

 B) tropical regions generally have more available water and higher levels of solar radiation.

 C) higher temperatures cause more rapid speciation.

 D) diversity increases as evapotranspiration decreases.

#Question id: 11333

#Unit 10. Ecological Principles

Small geographic areas with high concentrations of endemic species and a large number of endangered and threatened species are known as