Building models doesn't actually help scientists observe phenomena. Scientists build models to describe how nature and systems operate then make observations to see if their models match what they observe. Models which don't match what they observe are either alterated or scrapped. Good models are kept and used by the scientific community.
Answer:
Humans have greatly increased the level of in the atmosphere. O A. argon B. oxygen O . C. carbon dioxide O D. nitrogen
=carbon dioxides
The answer is They help control what enters and leaves the cell
Answer:
The water is transported to the top most leaves (and rest of its parts) of a tall tree by three actions:
1) root pressure (osmosis)
2) capillary action (adhesion)
3) evapotranspiration (cohesion)
Explanation:
The trees contain a series of interconnected tissues (xylem and phloem) that act as network for transport of water and nutrients throughout the tree. The root pressure and capillary action push the water, while the transpiration from the leaves pull the water. The root pressure is generated by osmotic movement of water from soil to the root tissues. The capillary action is caused due to adhesion of water molecules. However, root pressure and capillarity is thought to support only few meters of water column. The rest of the water transport (esp. in tall trees) is attributed to negative pressure generated by evaporation of water from leaves. This negative pressure creates a vacuum and pulls the water from the roots.
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