The correct answer is (b.) an increase in the width of the stem. The increase in the width of the stem could be referred to as the secondary growth of the stem. Whereas the primary growth is the upward growth of the plant.
2 examples -
1.) in italy, ( limone ) a unique mutation protects them from developing atherosclerosis,
2.)theres mutation in bacteria too, this mutation allows bacteria to survive in the presence of antibiotic drugs, leading to the evolution of antibiotic-resistant strains of bacteria.
The first question is B. false, The answer to the second question is stolon.