Navaratna : The nine gems of significance in Hindu tradition which are believed to be capable of radiating certai energies and cosmic rays to the wearer. The nine ratnas are emerald (marathaka), diamond (vajra), pearl (muthu), coral (pavizham), topaz (gomedika), blue saphire (indraneela), cat's eye (vaidurya), yellow saphire (pushyaraga), ruby (manikya).

Natural selection : The process by which evolutionary change take place in animals and plants. In the struggle, only the fittest survive.