<em><u>DNA are important molecules that carry hereditary information in all organisms. The nucleotide sequences or the genes are subject to change as a result of mutations.</u></em>
<em><u>Mutations are spontaneous random changes that occur in the genetic make up of an organisms or the DNA sequences of an organism.</u></em>
<em><u>When mutations occur they can cause insertion of new DNA segments, substitution of DNA sequences with new ones, and also deletion of some sequences of DNA.</u></em>
<em><u>Substitutions, deletions and insertion mutations are types of mutations that affect cells at gene level. </u></em>
Answer: The vulnerable embryo must be sheltered from desiccation and other environmental hazards. In both seedless and seed plants, the female gametophyte provides protection and nutrients to the embryo as it develops into the new generation of sporophyte.