Can we live only by eating vegetable /grass?Discuss.

Can we survive only on raw, leafy vegetables/grass? Discuss.

The reproduction is only by vegetative meansif the plant is:

In the following questions, out of the four alternatives, choose the one which can be substituted for the given words/sentence. One living on vegetables

Grass in lawn grows equally thick and in a uniform rate. It takes 24 days for 70 cows and 60 days for 30 cows to eat the whole of the grass. How many cows are needed to eat the grass in 96 days?