(c) Inherited a mutation in a gene required for mismatch repair
Explanation:
Gene mutations are occasional changes that occur in genes, that is, the procedure by which a gene undergoes a structural change. Mutations involve the addition, deletion or substitution of one or a few nucleotides of the DNA strand. Mutation provides the emergence of new forms of a gene and, consequently, is responsible for gene variability.
It is common for several members of the same family to have the same genetic mutations, as the gene affected by the mutation may condition a trait that DNA cannot repair. An example of this is the family shown in the question above, where several people were diagnosed with the same type of cancer while still young. What probably happened in this family was that people diagnosed with cancer inherited a mutation in a gene needed to repair incompatibility.
They contain symbiotic bacteria called rhizobia within nodules in their root systems, producing nitrogen compounds that help the plant to grow and compete with other plants. When the plant dies, the fixed nitrogen is released, making it available to other plants; this helps to fertilize the soil.
