The X plant leave morphology suggests that thick wax coating of leaf helps it to retain water in it. Such plants are called conifers. They are not shed every year so suitable for sunlight to be captured for photosynthesis. In cold regions heavy wind happens cone like leaf is able to resist the winds and prevent it from falling. The cone like structure of leaves help them let the snowfall.
The plant Y leaves and root morphology suggests that it is well suited for dry lands or desert as where less water is there. They store water for longer time when it rains because of the extensive root system. The spine leaves help in reduced transpiration as water scarcity is there.
The plant Z leaves morphology suggests that thin and ribbon structure leaves can help them resist the pressures of flowing water as there are air space in the leaves which provide buoyancy to the leaves.
A scientific hypothesis is an educated guess that is made about an observation based on the prior knowledge of the scientist. Hypothesis are always testable. An hypothesis can be tested through experimentation and it can also be tested through deductive methods.
