Plants, which are autotrophs, make their own food, glucose, using photosynthesis. They use light energy to fuel their chemical reactions. The energy from the sun gets transferred to organisms who consume it, or organisms who consume these herbivores. Ultimately, all sources of food are dependent on the sun's energy, and the energy used to walk your dog comes from light energy transferred into your food. Hope this helps, and let me know if you need any more help! :)
Energy from sunlight is being used in an indirect way for walking the dog. Plants photosynthesize in which they absorb energy from sun and convert it into chemical energy, which is stored in organic product formed as a result of photosynthesis. When this organic compound is consumed by us, we use the chemical energy stored in that food to mechanical energy for walking the dog. Hence, the energy to walk the dog comes from sunlight.
Carbon forms the key component for all known life on Earth. Carbon is the basis of all molecules. Its is easily able to bond because of the 4 valence electrons.
