Three characteristics that <span>trees used to build treehouses should have are: </span>- trees should be part of a long-lived hardwood. This is important in order maximum support to be achieved. - trees should have load-bearing branches at least 8 in. in diameter , also for better support <span>- trees should be mature, healthy and strong. . Healthy and strong trees are more stable and supportive. </span>The reason for the all mentioned characteristics is the safety.
Explanation: The basic unit of a DNA is a Nucleotide. The nucleotide comprises of: the nitrogenous bases, a deoxyribose sugar and a phosphate group. The nitrogenous bases are the purines and pyrimidines . The include, Adenine, guanine, Thymine and cytosine