$\begin{array}{1 1} \text{a.Shorter food chains provide more energy as compared to longer food chains.} \\ \text{b.Ecological factors connected with physical geography of the earth are called topographic factor.} \\ \text{c.The pyramid of biomass is upright in a grassland ecosystem and pyramid of numbers is upright in a parasitic food chain.} \\ \text{d.None of the above.} \end{array}$