a.

Commensalism

b.

saprophytes

c.

symbiosis

d.

parasitism

a.

A sand dune

b.

A bare rock

c.

A land that has just had a forest fire

d.

A stretch of barren land

a.

Stealing

b.

Sneezing

c.

Fighting

d.

Cheating

a.

cessation of photosynthesis

b.

wilting

c.

turgidity

d.

discolouration of leavess