Some tortoises that feed on grasses were observed on an island some years later environmental change cause the grasses to grow a bit higher off the ground but involuntary future will you expect to see in a tortoises on the island1. the tortoises will develop longer necks2. the tortoises will develop a thicker shells3. the tortoises will develop longer tails4. the tortoises will develop thicker tongues

1. the tortoises will develop longer necks

Explanation:

Organisms develop adaptive traits to make themselves better adapted to their surroundings. Evolution of taller grasses on the island would lead to the evolution of long necks in tortoises to prevent them from starving.  

The tortoises with a longer neck would be favored by natural selection due to their survival advantage. They will leave more progeny. Gradually, the population would consist of tortoises with a longer neck.  

helicase, i think thats it