Difference between including and prepending modules into class

module_inc_prep.rb

puts '===> INCLUDE EXAMPLE'

module M1
  def run
    puts 'M1 run'
  end
end

class C1
  include M1

  def run
    puts 'C1 run'
  end
end

puts C1.ancestors.join ', '

C1.new.run

puts '===> PREPEND EXAMPLE'

module M2
  def run
    puts 'M2 run'
  end
end

class C2
  prepend M2

  def run
    puts 'C2 run'
  end
end

puts C2.ancestors.join ', '

C2.new.run

# Output:
#
# ===> INCLUDE EXAMPLE
# C1, M1, Object, Kernel, BasicObject
# C1 run
# ===> PREPEND EXAMPLE
# M2, C2, Object, Kernel, BasicObject
# M2 run