The correct answer is option C
The original source of energy is the sun while most of the energy in the organisms is used in the form of energy. The energy from the sun is used by the green plants to make food by the process of photosynthesis and this food is used by the human beings and animals. The energy in animals and human is in the form of ATP.
The brain can determine the static position of the head due to sensors in the Vestibules
The "GM" here refers to "genetically modified" plants - they are modified by food engineers to better suit our wishes.
One benefit of those plants is that those plants would be better for humans: for example they would have sweeter flesh or less seeds (this is something that happened to watermelon through the selection of best watermelons throughout the centuries).