The technique used to detect specific proteins in a tissue section using labeled antibodies is: MCQ with Answer and Explanation

Explanation:
The Munch hypothesis, or mass flow hypothesis, explains the movement of sugars (primarily sucrose) through the phloem. It proposes that sugars are actively loaded into the phloem at the source (e.g., leaves), which lowers the water potential and causes water to enter from the xylem by osmosis. This creates a high turgor pressure. At the sink (e.g., roots, fruits), sugars are unloaded, increasing water potential, and water leaves the phloem, creating a low turgor pressure. The bulk flow of sap is driven by this turgor pressure gradient from source to sink.

Explanation:
Oxytocin, produced in the hypothalamus and released from the posterior pituitary, triggers the milk let-down reflex by causing myoepithelial cells around alveoli to contract upon suckling. Prolactin stimulates milk synthesis. Estrogen and progesterone are involved in breast development during pregnancy but not the immediate ejection reflex.

Explanation:
The nucleus is bounded by a double membrane called the nuclear envelope, not a single membrane. It houses the nucleolus, which is the site of ribosomal RNA synthesis. The nuclear envelope is perforated by nuclear pores that regulate the bidirectional transport of molecules, including the export of mRNA to the cytoplasm. Thus, statements 2 and 3 are correct.