What factors contributed to increased interest in conservation in the 1960s?

The Environmental Movement and the First Earth Day. Learn about the first Earth Day in this video from the American Masters film, A Fierce Green Fire. Interest in conservation increased during the 1960s as people became more aware of pollution, endangered species, and Earth's unique characteristics.

There are no choices available but, based on the theory mentioned in the question, giraffes developed long necks because the food that they primarily consumed also evolved or has grown through time. The need to feed and survived probably led the giraffes DNA to decode and adapt within its surroundings, hence making giraffes have long necks that precedes the evolution of the plant that they eat.