But researchers do not know how plants in a natural state respond to such increases.

One even hears that plants respond to the spoken word!

Recent studies provide evidence that even certain plants can recognize and respond to kinship ties.

It has been found that these plants only respond to objects of nutritional value and not to sand, paper, or water.

The notion that plants respond to sweet talk and music amused him.

Some plants may respond to more than one of these triggers.

These plants can respond to changes in demand rapidly, but have higher operating costs.

He then asks who wrote about mountains, and the plant responds.

Animals and plants respond to these changes through a process known as photoperiodism.

"The plants will respond quickly and do very well."