Ah, a definition of life in Namibia for a grade 12 course. Quite the scientific authority you have there.

Here's a short paper (Origins of Life and Evolution of the Biosphere 32, 387-393, 2002) that refutes your position that a single definition of life is definitively agreed upon.

Here's a paper (Synthese, 2012) on how a definition of life is impossible and pointless.

There is a species of dog that infects other dogs as a parasite. There are viruses with larger genomes than some bacteria. Obligate parasites and endosymbiotes often lose large portions of their genome and depend on their hosts for their vital functions. Nature doesn't care about are definitions, and biology hates hard cutoffs.