<em>The answer is endoplasmic reticulum</em>
When that object is first introduced to a different environment.
Cellular respiration happens in all eukaryotic cells and it occurs in the mitochondria, the powerhouse of the cell. cell resp breaks up glucose in order to create more ATP for the cell. the products that go IN are GLUCOSE and OXYGEN. the products that come OUT are CARBON DIOXIDE, WATER, and of course, ENERGY.
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.