If beak variation came about because of competing species evolving different adaptations, then what is the reason beak variation came about in birds?

Answer choices:
- By wind and rain
 - Attracting mates
 - It helps them survive
 - the Earth being tilted
 - Competing species evolving
 - it keeps an organism warm
 - To assist in flying
 - Warding off predators

 

     Competing species evolving     