Natural regeneration of forests and woodlands is the process by which new trees grow from seeds that have fallen and germinate where they have fallen. The biggest problem with natural regeneration is that is unpredictable. As a result, it cannot be used for commercial farming. For most of the last two or three hundred years, forests and woodlands have restocked by using transplants grown in nurseries. The young trees are planted in equidistant rows. This allows each tree the best possible change of optimal growth.
My best guess would be c because b makes no since we as humans do not have photosynthesis and are considered living organisims, d is also wrong because the brain requires oxygen, and its not a because the brain is made of cells.
Answer:
c. mid-adulthood
Explanation:
This stage of life when gray hairs become overwhelming in number and he has more gray hairs than brunette( brown hair) is called middle adulthood. Middle adulthood spans from 20 to 40 years of life which may be defined differently for different culture and country.
Robert is in his late mid adulthood somewhere near 40 at this age hair generally grow grey.
The sun rays are received by the plants and explell oxygen and we breath the oxygen to be able to survive