Singular/Plural & This/These (Fruit)

His YouTube profile says that he is from Egypt and is 33 years old.

a peach / 2 peaches
an apple / 2 apples
a mango / 3 mangoes
a strawberry / 3 strawberries
a watermelon / 3 watermelons

this apple / that apple
these apples / those apples

What is this? / What is that?
It is an an apple.
This is an apple.
That is an apple.

What are these?
They are apples.
These are apples.