sentences: a human is a kind of animal & an animal is a kind of living thing ->  a human is a kind of living thing  an apple tree is a kind of plant & a plant is a kind of living thing ->  an apple tree is a kind of living thing  a human is a kind of living thing & an apple tree is a kind of living thing & all living things are made of cells according to the cell theory -> both the human and the apple tree are made of cells