When a peacock eats a snake,which eats insects,and insects feed on green plants,the peacock is a/an:

Ecological succession represents .........

What is the primary succession in freshwater called?

Which light is transmitted by water?

Which of the following are the essential sources for releasing $CO_{2}$ into the atmosphere?
$I.$ Burning of wood
$II.$ Volcanic activity
$III.$ Combustion of organic matter
$IV.$ Fossil fuels
Choose the correct option.

Choose the correct sentence.