Every living organism produces another organism like itself. What is this phenomenon called?

"The consistency of $DNA$ copying during reproduction is important for the maintenance of body design features." Support this statement with two arguments.

Regeneration is not possible in all types of animals. Why?

Reproduction is essential for living organisms in order to

$(a)$ Identify the asexual method of reproduction in each of the following organisms:
$(i)$ Rose
$(ii)$ Yeast
$(iii)$ Planaria
$(b)$ What is fragmentation? Name a multicellular organism which reproduces by this method.

What is the main cause of variations among organisms during sexual reproduction?