City X is at a distance of 560 km from City Y. A train starts from City Y to City X at 6 a.m. with a speed of 40 kmph. Another train starts from City X to City Y at 7 a.m. with a speed of 60 kmph. At what distance from City Y will the two trains be at the point of crossing?

#Question id: 11710

#Unit 9. Diversity of Life Forms

Why is the filamentous morphology of the water molds considered a case of convergent evolution with the hyphae (threads) of fungi?

#Question id: 11711

#Unit 9. Diversity of Life Forms

The Irish potato famine was caused by an organism that belongs to which group?

#Question id: 11712

#Unit 9. Diversity of Life Forms

The following are all characteristic of the water molds (oomycetes) except

#Question id: 11713

#Unit 9. Diversity of Life Forms

Theoretically, which two of the following present the richest potential sources of silica?

1.  marine sediments consisting of foram tests

2.  marine sediments consisting of diatom cases (valves)

3.  marine sediments consisting of radiolarian shells

4.  marine sediments consisting of dinoflagellate plates

#Question id: 11714

#Unit 10. Ecological Principles

In recognizing patchiness in the natural world, ecologists have developed three different models of populations. Which of these recognize(s) that there are differences in the quality of habitat patches without considering effects of differences in habitat quality within the habitat matrix?

#Question id: 11715

#Unit 10. Ecological Principles

The lifetime dispersal area of a particular species of drosophila is 0.2 km2. What else would we need to know to determine the neighbourhood size for this species?