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
For Question 19:
To determine the correct answer, you need to have knowledge about the process of secondary growth in plants.
Secondary xylem and phloem are formed from a tissue called vascular cambium. This tissue is responsible for the production of secondary xylem (wood) towards the center of the stem and secondary phloem towards the outside.
The cork cambium produces the cork cells, which form the protective outer layer called bark. Apical meristems are responsible for primary growth and not the formation of secondary tissues.
Based on this information, the correct answer is B) vascular cambium.
For Question 7:
To determine the correct answer, you need to understand the differences in germination between beans and corn.
The statement "the cotyledons are above ground in the bean plant" is true. Cotyledons are the seed leaves, and in beans, they emerge above the ground during germination.
The statement "the corn shoot is hooked to protect it from damage" is not true. Corn shoots do not have a hooked structure during germination.
The statement "the bean plant cannot germinate until water penetrates the seed coat" is also true. Water is required to penetrate the seed coat (testa) of the bean seed to initiate germination.
The statement "oxygen is required in the seed before a corn plant can germinate" is not true. Oxygen is indeed required for germination in both beans and corn.
Based on this information, the correct answer is A) the cotyledons are above ground in the bean plant.
For Question 8:
To determine the correct answer, you need to understand the role of the cork cambium in a woody stem.
The cork cambium is responsible for producing cork cells, which accumulate to form the outer bark of a woody stem. This outer bark provides protection to the underlying tissues.
The cork cambium does not produce sieve tubes (phloem cells) or vessel cells (xylem cells). Likewise, it does not transform into the vascular cambium.
Based on this information, the correct answer is C) produces the cells of the outer bark.