In general what is the effect of the type of medium on diffusion rate

Answer

          The rate of diffusion is strongly affected by the type of medium.

Viscosity of medium

         if the medium is more viscous then the rate of diffusion will slow.  However if the medium is less viscous then the rate of diffusion will be faster.

Chemical nature of medium

          If the nature of medium is same as that of molecules entering or leaving the medium. then the rate of diffusion will be faster. on the other hand if the nature of medium and molecules leaving or entering the medium is different the n rate of diffusion will be affected.

State of medium

           State of medium have also effect on rte of diffusion. like gas molecules can easily diffuse across gas medium as compared to liquid or solid medium.

the correct answer is - d. china has a large and growing population.

the fact that china has a large (the biggest) population, and it is still growing, doesn't hinder the agriculture production in the country. in fact, it can for increased production in the agriculture, since there's more labor force, as well the sheer mass of people produces lots of scientists that come up with new inventions as to how to improve this sector. nice example is the inner mongolia region in china, in general dominated by the gobi desert, but few scientist came up with a nice idea as to how to make the region productive by using plants that are very resistant to droughts, so lots of people have been employed, and the region is becoming greener and greener each year, and the production of food in this region is also increasing.