"D. All of the above is the correct answer in terms of the difficulty associated with environmental protection. Cost, however, is probably the most important issue of the list.
Pressure Flow. The mechanism by which sugars are transported through the phloem, from sources to sinks, is called pressure flow. At the sources (usually the leaves), sugar molecules are moved into the sieve elements (phloem cells) through active transport.
Answer:
<h2>Answer : Both A and B.</h2>
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Here are the importance of nitrogen's to living things:
- It helps cells make proteins, Nitrogen's help in the processing of amino acids that essential in structuring a protein.
- It provides a form of usable nitrogen , this process is known as nitrogen fixation and crucial for many lifeforms in their metabolism