The stem has more things to transport that's why it has more vascular bundles. The roots only get water from the ground and moving nutrients from the soil to transfer it to the stem. Having more vascular bundles helps the stems to transfer things to leaves and other parts of the plants.
Organisms that reproduce sexually have greater genetic and thus characteristic variations, and so, are able to withstand more selection pressures if they so happen to change or become greater. This increases the chances of survival for that species itself.
Organisms that reproduce asexually are genetically identical to each other. They are unlikely to withstand any changes in selection pressures.
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Answer:
hereditary variat on selection is made of those genetic variats that well be passed on most effectively to the following generation
Both organs and variety of organisms have bone , body parts like legs , arms and many more.