Which type of region on Earth shows the maximum biodiversity and the richest variety of living species?

Introduction / Context:
This question tests understanding of biodiversity patterns on Earth. Biodiversity refers to the variety of life forms in a given area, including species of plants, animals, and microorganisms. Different regions of the planet support different levels of biodiversity based on climate, energy input, and environmental stability.

Given Data / Assumptions:

• Deserts are dry regions with low rainfall.
• Rivers are freshwater ecosystems that flow through many climate zones.
• Polar regions are extremely cold zones near the poles.
• Tropical regions lie around the equator with warm temperatures and usually high rainfall.

Concept / Approach:
Biodiversity is highest near the equator and decreases towards the poles. Tropical regions, especially tropical rainforests and coral reefs, are known as hotspots of biodiversity. They provide stable warm temperatures, high solar energy, and abundant rainfall, which support dense, complex ecosystems with many species. Deserts and polar regions tend to have fewer species due to harsh climatic conditions, and while rivers can be rich in life, they do not match the overall diversity of tropical regions.

Step-by-Step Solution:

Verification / Alternative check:
Ecology textbooks often provide graphs that show species richness by latitude. These graphs rise sharply towards the equator, illustrating that tropical zones have the highest number of species. They also discuss specific examples such as the Amazon rainforest and coral reefs in tropical seas, which support far more species than most deserts or polar regions.

Why Other Options Are Wrong:

• Desert is wrong because harsh dry conditions limit the number of species that can survive.
• River is wrong because, although rivers are productive ecosystems, their total species count is lower than that of extensive tropical forests and reefs.
• Polar Region is wrong because extremely cold temperatures and long periods of darkness restrict biodiversity.

Common Pitfalls:
Some learners may focus on the idea that rivers always contain life and might overestimate their biodiversity. Others may think deserts are interesting and exotic and forget that species numbers are low there. Remember the simple rule that warm, wet, and stable environments near the equator tend to have the greatest biodiversity.

Final Answer:
Tropical Region