1. Involuntary actions like blood pressure, salivation and vomiting are controlled by the medulla.

2. The medulla oblongata, also called the medulla, is the lowest part of the brain and the lowest part of the brainstem.

3. The medulla oblongata or simply the medulla is a long stem-like structure that is part of the brain.

Metals are electropositive elements because they tend to lose electrons easily. In chemical reactions, metals readily give away their outer electrons to form positive ions, making them good conductors of electricity and heat. This electron loss leads to the formation of cations, which contribute to the electropositive nature of metals.

The yellow color of human urine is primarily due to a pigment called urochrome. Urochrome is a waste product resulting from the breakdown of hemoglobin, a protein in red blood cells. The varying shades of yellow in urine can be influenced by factors such as hydration levels, diet, and certain medications, but urochrome is the main pigment responsible for the typical yellow color of urine.