Which tissue is responsible for the increase in the girth of a dicot stem? MCQ with Answer and Explanation

Explanation:
In cymose inflorescence, the main floral axis has limited growth and terminates in a flower. Subsequent flowers are produced by lateral branches, which also terminate in flowers, creating a sympodial growth pattern. This is in contrast to racemose inflorescence, where the main axis continues to grow indefinitely (monopodial) and flowers are arranged in an acropetal or basipetal order.

Explanation:
Galanin is a 29-amino acid neuropeptide that is co-localized with several other neurotransmitters and hormones. In the central nervous system, it is involved in various functions, including the inhibition of acetylcholine release and modulation of pain. In the gastrointestinal tract and pancreas, its primary functions are inhibitory: it inhibits the release of both insulin and glucagon from the pancreatic islets, inhibits gastric emptying and gastric acid secretion, and generally inhibits intestinal motility and secretion. It acts to slow down digestion and nutrient absorption.

Explanation:
RNAi is a cellular defense mechanism in eukaryotes that silences specific mRNA. To create nematode-resistant tobacco, scientists used Agrobacterium as a vector to introduce nematode-specific genes into the host plant. The plant then produced both sense and anti-sense RNA for these genes. The double-stranded RNA (dsRNA) formed triggered the RNAi pathway, degrading the nematide's mRNA when it tried to express those essential genes inside the plant roots, killing the nematode.