Mao says that life exists due to contradictions and that once those contradictions cease, we die. But which are the contradictions which cause us to be alive? To me it is more cell cooperation than contradictions. I am not sure to which contradictions he is referring to.
It wouldn't be called cooperation if that system itself didn't have contradictions like cells sacrificing themselves to clot blood, overriding their self interest to remain alive. Cells are also marked for death and if they break that system they can bring down the whole structure (cancer, auto immune disorders). Cells have to balance their self interests with their communal interests and that contradiction creates a higher level of organization than the simple parts (cooperation).
Another, more basic contradiction is requiring energy to be alive because living (action) requires energy, so we always need to be using energy to find energy (it takes energy to produce and consume food). If we don't get enough energy to sustain ourselves we waste away into death.