Question

In ferns, both the gametophyte and sporophyte are physiologically capable of surviving on their own. Which of the following are reasonable hypotheses for why vascular tissues are present only in the sporophyte generation? Select all that apply.
There is no advantage for the gametophyte to grow tall, because fern gametophytes typically produce only male or female gametes at any one time

There is no advantage for the gametophyte to grow tall, because gametes must be produced near the ground where the water needed for their free-swimming sperm is most likely to be found

Haploid organisms are incapable of developing vascular tissues, such as xylem and phloem

Vascular tissues are incompatible with desiccation tolerance

How do the flowers of angiosperms differ from the cones of earlier diverging seed plants? 

Flowers do not produce spores

Flowers are typically bisexual, producing both male and female gametophytes

Flowers have adaptations for pollen capture

Flowers allow an individual sporophyte to self-fertilize

Grapes growing on a vine are observed to shrink slightly during the day, only gaining in size at night. You decide to do an experiment where you sever the phloem, but not the xylem, of the stem that supplies a cluster of grapes. You expect to see that for the grapes in the experimental cluster:

shrinkage during the day stays the same, and while size recovers at night, it no longer increases

shrinkage during the day becomes more noticeable, and while size recovers at night, it no longer increases

grape size increases during the day and shrinks at night

all changes in size cease

Answer 1

Answer:

a) First hypothesis is true.

Vascular tissue is supposed to transport water and minerals to heights.Gametophytes cant grow too high, as haploid sperm and ovum needs to come down for fusion.

Second hypothesis is also true, gametophyte (adult) is haploid and sporophyte is diploid.

But testing will make this hypothesis fail, because haploid plants with vascular tissue is grown in cultures.

The third hypothesis cannot be put forward. This is because plants like cactus with high dessication tolerance (resistance to extreme drought) has got vascular system.

b) flowers have both ovum and pollen in same flower and typical mechanism for pollination.

But in cones, female cones and male cones are separate. The pollen from male cone should reach female cone through air.

c) xylem transport water and minerals. Phloem transport prepared food and water from leaves.

Phloem allows bidirectional flow, where xylem flow is unidirectional.

When phloem is sever the down transport of food in water is blocked in day time.

So grape will shrink more at day as water with food is not transported to grapes during day. In night no photosynthesis so size recovers in night, but it will never increase in size as no more food to grapes.