Answer:
The correct answer would be B. lipids.
Lipids are organic compounds which are insoluble in polar solvents such as water and are soluble in non-polar solvent such as ether.
They are essential for proper functioning of the body.
They serve various functions such as:
Energy storage: Excess of food we eat is converted into fats and is stored in adipose tissues. They serve as the source of energy when levels of glucose are low in the blood.
Insulation: Lipids helps in maintaining the constant internal temperature of the body. Subcutaneous fats serve as the blanket layer around the tissue which aids in insulating the body against external temperatures. Triglycerides are mainly involved in thermal insulation and sphingolipids are mainly involved in electrical insulation.
Protection: Visceral fat (layer of fat around the internal organs) act like bubble wrap around the internal organs and protect them from injury, trauma or shock.
Other functions may include structural component (plasma membrane), hormonal roles (such as steroidal hormones), absorption of fat-soluble vitamins et cetera.
