Why would the tissues of a leaf need to have the ability to resist changes in pH in their natural environment? i. e. what is the source of acid or base is that a leaf might be exposed to under normal circumstances?

The tissues of a leaf needs to have the ability to resist changes in their natural environment so that they can survive

explanation:

b,bacteria convert nitrates

into nitrogen gas.

d,plants and animals take in

and use nitrogen compounds.

e,bacteria break down waste    

products and return nitrogen  

to the soil.

a,bacteria convert atmospheric

nitrogen to ammonia.

c,bacteria convert ammonia

to nitrites and nitrates.

this age may represent the age of the earth's accretion, of core formation, or of the material from which the earth formed. this dating is based on evidence from radiometric age-dating of meteorite material and is consistent with the radiometric ages of the oldest-known terrestrial and lunar samples.