Acetylene is the only fuel gas suitable for gas welding because of its favourable flame characteristics of both high temperature and high propagation rates. Other fuel gases, such as propane, propylene or natural gas, produce insufficient heat input for welding but are used for cutting, torch brazing and soldering.

The study of properties and methods of biological systems found in nature and the application of this knowledge in the design and improvement of artificial systems is known as:

(A) Bionics

Explanation:

Bionics: Bionics is an interdisciplinary field that combines biology and engineering. It involves studying natural systems to understand their design and functionality and then applying this knowledge to create or improve artificial systems. The goal is to develop technologies inspired by nature. For example, designing a robot based on the principles observed in animal locomotion or creating materials inspired by the structure of biological tissues.

The other options:

Bionomics: This term is more commonly associated with the ecological study of organisms and their relationships with each other and their environment.

Bionomy: This term is not commonly used, and its meaning can vary in different contexts.

Biometry: Biometry usually refers to the statistical analysis of biological data.

Therefore, the correct answer is (A) Bionics.

(A) Small Intestine

The absorption of nutrients from food primarily occurs in the small intestine. The small intestine is a long, coiled tube that follows the stomach in the digestive tract. It is the primary site for the absorption of nutrients such as sugars, amino acids, fatty acids, vitamins, and minerals into the bloodstream. The small intestine has specialized structures called villi and microvilli that increase its surface area, facilitating efficient absorption of nutrients. The large intestine primarily absorbs water and electrolytes but is not the main site for nutrient absorption. The stomach plays a role in digestion but is not a major site of nutrient absorption. The liver is involved in processing and storing nutrients but does not directly absorb them from the digestive tract.