Prairie dogs once covered the expanses of the Great Plains. Their grazing made the grass more nutritious for the huge herds of bison, and a variety of snakes, raptors, and mammals   preyed on the rodents. In fact, the black- footed ferret (now endangered) specialized in prairie dog predation. Today, growing housing and agricultural developments have covered many prairie dog towns. Which of the following statements about prairie dogs is true?

#Question id: 11743

#Unit 6. System Physiology – Plant

The wall between the two mature sieve tube elements contain a sieve plates, these sieve plate pores are open —that is, unobstructed by

#Question id: 11744

#Unit 6. System Physiology – Plant

Large pores in cell walls are the prominent feature of sieve elements, the sieve area pores range in diameter from

#Question id: 11745

#Unit 6. System Physiology – Plant

sieve cells of the sieve elements of phloem conduct sugars throughout the plant. The following statements given about characteistics of Sieve cells of sieve elements in seed plants;

a.)  There is no P-protein in gymnosperms

b.) Angiosperm contains sieve plate pores are open channels

c.) Pores in sieve areas appear blocked with membranes in gymnosperms

d.) Companion cells are sources of ATP and perhaps other compounds

Which of the following combination is correct?

#Question id: 11746

#Unit 6. System Physiology – Plant

Sieve element sap is rich in sugars and other organic molecules, These molecules represent an energy investment for the plant. How their loss be prevented when sieve elements are damaged?

#Question id: 11747

#Unit 6. System Physiology – Plant

A mechanism for preventing sap loss entails closing sieve plate pores with callose, which is

#Question id: 11748

#Unit 6. System Physiology – Plant

In mature cells, P-protein occurs in several different forms depending on the species. Such as;