The human heart has only 4 chambers. Left and right atria and left and right ventricles.
Explanation:
Whereas primary tissues allow for vertical growth, secondary tissues allow for lateral growth: they allow stems and roots to become wider. In roots, the formation of both secondary meristems involves the pericycle.
Transcription is the process<span> by which </span>DNA<span> is </span>copied<span> (transcribed) to mRNA, which carries the information needed for protein synthesis. Transcription takes place in two broad steps. First, pre-messenger </span>RNA<span> is </span>formed<span>, with the involvement of </span>RNA<span>polymerase enzymes.</span>