Nucleus. The answer is this because:
The nucleus is the central and most important part of a cell and so it directs the cell activities.
Ribosomes make protein, sometimes that protein is needed when repairing cellular damage. The correct answer is A.
Electromagnetic waves are waves that have no medium to travel whereas mechanical waves need a medium for its transmission. Electromagnetic waves travel in a vacuum whereas mechanical waves do not
The relationship between legumes and rhizobium is <span>mutualistic.
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