Find the odd one with respect to tropics $-$

According to the hypothesis proposed by environmental biologists,a relatively constant environment in the tropics promotes:

Species diversity increases as one moves from .......... .

Choose the incorrect sentence$(s)$ regarding latitudinal gradients.
$(I)$ Biodiversity throughout the world shows uneven distribution.
$(II)$ According to latitudinal gradient,there is no major difference in biodiversity.
$(III)$ Species diversity increases as we move away from the equator towards the poles.
$(IV)$ Biodiversity increases as we move from temperate to tropical regions.

Provide detailed information about the species-area relationship with the help of a graph. Explain the representation of the species-area relationship and how it becomes linear on a logarithmic scale.

Biodiversity is affected by