The bulk fixation of carbon through photosynthesis takes place in

Solar energy is converted into chemical energy by plants,and this chemical energy is converted into kinetic or heat energy in animals. This process demonstrates:

Match the following columns:

Column-$I$	Column-$II$
$P$. Herbivores	$I$. Directly dependent on plants
$Q$. Carnivores	$II$. Indirectly dependent on plants
$R$. Saprophytes (Fungi)	$III$. Dependent on dead or decaying matter

Which of the following represents a tertiary consumer and a secondary consumer,respectively?

The order of organisms in an aquatic food chain is:

In hydrarch succession,the reed swamp stage is preceded by