Question

6) Define primary successiones evolution
7) Name the stress hormones in plant?
8) Name the causative agent in typhoid fever.
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Answer 1

Answer:

Primary succession, type of ecological succession (the evolution of a biological community's ecological structure) in which plants and animals first colonize a barren, lifeless habitat.

Abscisic acid (ABA), termed stress hormone, plays an important role in plant leaves abscission and abiotic stresses tolerance [3].

Cause. The typhoid bacillus Salmonella typhi, which infects humans only. Paratyphoid and enteric fevers are caused by other species of Salmonella, which infect domestic animals as well as humans.