19. The secondary xylem and phloem form from
a. cork cambium
b. vascular cambium
c. apical meristems
d. bark
B?
7. A difference between beans and corn during germination is
a. the cotyledons are above ground in the bean plant
b. the corn shoot is hooked to protect it from damage
c. the bean plant cannot germinate until water penetrates the seed coat
d. oxygen is required in the seed before a corn plant can germinate
A?
8. In a woody stem, cork cambium
a. forms phloem by producing sieve tubes
b. forms xylem by producing vessel cells
c. produces the cells of the outer bark
d. becomes vascular cambium
C?
-MC
19. The formation of secondary xylem and phloem involves the activity of a cambium tissue. The cork cambium is responsible for producing the outer bark, so option a is incorrect. The apical meristems are involved in primary growth, but not in the formation of secondary xylem and phloem, so option c is incorrect. The correct answer is option b, vascular cambium. The vascular cambium is a lateral meristem that is responsible for producing secondary xylem towards the inside of the stem and secondary phloem towards the outside of the stem.
7. The difference between beans and corn during germination is described in the options. The cotyledons are the seed leaves of a plant. In bean plants, the cotyledons emerge above ground during germination, so option a is correct. The corn shoot does not have any particular hook to protect it from damage, so option b is incorrect. The bean plant requires water to penetrate the seed coat to germinate, so option c is incorrect. The corn plant does require oxygen for germination, so option d is incorrect. The correct answer is option a.
8. In a woody stem, the cork cambium is responsible for producing the cells of the outer bark. It does not form phloem by producing sieve tubes, so option a is incorrect. It also does not form xylem by producing vessel cells, so option b is incorrect. The correct answer is option c, cork cambium produces the cells of the outer bark. The vascular cambium, on the other hand, is responsible for producing secondary xylem and phloem and does not become the cork cambium, so option d is incorrect.