DEFENCE SYSTEM
\dɪfˈɛns sˈɪstəm], \dɪfˈɛns sˈɪstəm], \d_ɪ_f_ˈɛ_n_s s_ˈɪ_s_t_ə_m]\
Word of the day
Quinones
- Hydrocarbon rings which contain two moieties position. They can be substituted in any position except at the ketone groups.