List and describe briefly five external factors that must be present or provided to sustain life.

Verified step by step guidance

1. Identify that the question asks for five external factors necessary to sustain life, which are environmental conditions or resources organisms depend on to survive.
2. List the first factor: Oxygen – essential for cellular respiration, allowing cells to produce energy.
3. List the second factor: Water – vital for biochemical reactions, temperature regulation, and as a solvent for nutrients and waste.
4. List the third factor: Nutrients – substances like carbohydrates, proteins, fats, vitamins, and minerals that provide energy and building blocks for growth and repair.
5. List the fourth factor: Temperature – must be within a range suitable for enzymatic and metabolic activities to function properly.
6. List the fifth factor: Pressure – atmospheric or hydrostatic pressure is necessary for processes like breathing and circulation in many organisms.

Key Concepts

External Factors for Life

External factors are environmental conditions or resources outside an organism that are essential for its survival. These include elements like water, oxygen, and temperature, which must be maintained within certain limits to support life processes.

Water as a Life Sustaining Factor

Water is crucial for life as it acts as a solvent, medium for chemical reactions, and helps regulate temperature. All living organisms depend on water to transport nutrients and remove waste, making it a fundamental external factor.

Oxygen and Atmospheric Conditions

Oxygen is vital for cellular respiration in most organisms, enabling energy production. Additionally, appropriate atmospheric pressure and temperature ranges are necessary to maintain biochemical stability and support metabolic activities.