Lichen is usually cited as an example of 'symbiosis' in plants where an algal and a fungal species live together for their mutual benefit. Which of the following will happen if algal and fungal partners are separated from each other?
$A$. Both will survive and grow normally and independent from each other.
$B$. Both will die.
$C$. Algal component will survive while the fungal component will die.
$D$. Fungal component will survive while algal partner will die.
Based on your answer,how do you justify this association as symbiosis?

(B) $\rightarrow$ The correct answer is $B$.
$\rightarrow$ Lichen represents an obligate mutualistic symbiosis between algae (phycobiont) and fungi (mycobiont). Both organisms live together for their mutual benefit.
$\rightarrow$ The fungal component provides protection,anchorage,and absorbs water and minerals from the environment,which it shares with the algal partner. In return,the algal component performs photosynthesis to provide organic food (carbohydrates) to the fungus.
$\rightarrow$ Because of this high degree of physiological interdependence,if the two partners are separated,they cannot survive independently in the harsh environments (like bare rocks) where lichens typically grow. Thus,both components are unable to sustain themselves without each other,justifying the association as an obligate symbiosis.