The gaseous plant hormone is: MCQ with Answer and Explanation

Explanation:
Peptide YY (PYY) is a gut hormone secreted by the L cells in the mucosa of the distal small intestine (ileum) and colon, primarily in response to food ingestion, especially fats. Its primary functions are related to the 'ileal brake' mechanism: it inhibits gastric emptying and pancreatic exocrine secretion, slowing down the transit of food through the upper GI tract to allow more time for digestion and absorption in the ileum. It also acts on the hypothalamus to reduce appetite, serving as a satiety signal.

Explanation:
Fossils are direct evidence showing transitional forms. Lamarck proposed use and disuse, not natural selection. Analogous organs do not indicate common ancestry; homologous do. Appendix is vestigial.

Explanation:
Root pressure is a positive hydrostatic pressure generated in the xylem of roots due to the active secretion of ions into the xylem, which lowers the water potential and causes water to enter osmotically from the soil. This pressure can push water up the stem. Root pressure is most evident and measurable during the early morning or at night, when the rate of transpiration from the leaves is very low (or zero) and the soil moisture is high, allowing for maximum water absorption. It is responsible for phenomena like guttation and the exudation of sap from cut stems.