There are at least three different types of companion cells in the minor veins of mature, exporting leaves. Which of the following statements about these companion cells is CORRECT?

 a.) transfer cells are transport sugars enter the apoplast during the movement of sugars from mesophyll cells to sieve elements. Transfer cells transport sugars from the apoplast to the symplast of the sieve elements and companion cells in the source.

 b.) the numerous mitochondria in companion cells may supply energy as ATP to the sieve elements

 c.) Ordinary companion cells can function in either symplastic or apoplastic short-distance transport in source leaves, depending in part on plasmodesmatal frequencies

 d.) Intermediary cells, by contrast, function in symplastic transport of sugars from mesophyll cells to sieve elements

TLS Online TPP Program

#Question id: 12256

#Unit 10. Ecological Principles

Ant species X preys upon ant species Y. A researcher has the following set of observations regarding the behaviour of species X where aggression signifies a predatory response.

Which of the following statement(s) are correct regarding the behaviour of Species X?

(i)    A glass bead is sufficient to elicit the predatory response.

(ii)   Both chemical and non-chemical cues are involved in the predatory response.

(iii)  Chemical cues are necessary to elicit the predatory response.

(iv) Chemical cues are sufficient to elicit the predatory response

TLS Online TPP Program

#Question id: 12257

#Unit 10. Ecological Principles

Which of the following is most likely to reduce competition in sympatric, closely related species? 

TLS Online TPP Program

#Question id: 12258

#Unit 10. Ecological Principles

The acoustical receptors are destroyed on a population of larvae and rates of wasp predation are measured on the "deaf” larvae and  on  a  population  of  normal  larvae.  Based on the  curve  in  the  figure  and  on  the  concept  that animals possess sensory mechanisms that enhance survival, one could correctly predict which of the following?

TLS Online TPP Program

#Question id: 12259

#Unit 10. Ecological Principles

Which of the following is an example of exploitation competition? 

TLS Online TPP Program

#Question id: 12260

#Unit 10. Ecological Principles

Chemical competition among organisms is referred to as __________. 

TLS Online TPP Program

#Question id: 12261

#Unit 10. Ecological Principles

When a person removed the predator Pisaster from rocky intertidal areas, the diversity of prey animals changed from 15 to __________.