STD 12 - 5. molecular basis of inheritance — Biology STD 12 Science — Question

$(1)$ Decomposition is largely an oxygen -requiring process.

$(2)$ Warm and moist environment slow down decomposition process.

$(3)$ Decomposition rate is slower if detritus is rich in lignin and chitin

$(4)$ Humus is colloidal in nature it serves as are servoir of nutrients.

$I$. Removal of $80\; \%$ tigers from an area resulted in greatly increased growth of vegetation.

$II.$ Removal of most of the carnivores resulted in an increased population of deers.

$III.$ The length of food chains is generally limited to $3$ to $4$ trophic levels due to energy loss.

$IV.$ The length of food chains may vary from $2$ to $8$ trophic levels.

Which two of the above statements are correct?