Which of the following is not a reason that accounts for greater biodiversity of tropics?

1. availability of more solar energy
2. more niche specialization
3. more time for species diversification
4. large seasonal variations in environmental factors

The greatest biodiversity on the earth is found in
1. African grasslands
2. Amazonian rain forest in South America
3. Western Ghats in India
4. Nile delta in Egypt

The relation between species richness and area for a wide variety of taxa on a logarithmic scale is a:

1. rectangular hyperbola

2. straight line

3. sigmoid curve

4. sine curve

Alexander von Humbolt described for the first time 
(1) ecological biodiversity

(2) law of limiting factor

(3) species area relationships

(4) population growth equation 

Presence of plants arranged into well defined vertical layers depending on their height can be best seen in

(1) tropical savannah

(2) tropical rain forest

(3) grassland

(4) temperate forest