Answer
D. It keeps chemicals from entering the watershed
Explanation
Agricultural run off can be described as the disposal of artificial fertilizers , pesticides, herbicides, sewages etc into which drained off into oceans , lakes and ponds with water .
Agricultural run off is recycled , then water will be less polluted , the water therefore be not harmful for usage by the plants/crops & it will make the drained water less contaminated for the Aquatic living in the ocean , rivers , lakes or ponds
With a light microscope one can view the nucleus and endoplasmic reticulum, large vacuoles etc
The resolution of a light microscope is dependent on the wavelength of light that is the main beam of illumination. Light has approximately 0.4 um (UV)- 0.7um (Infrared) wavelength. Organelles smaller than about 0.5 um will be difficult to discern with a light microscope.
With an electron microscope one can view, in addition, even the ribosomes and mitochondria, chromosomes, tubules etc.
An electron microscope can discern very minute details of a cell. This is because its resolution is dependent on the very small wavelength of a beam of electrons which is approximately 0.002 um (about 10,000 times powerful than a light microscope)
<span>DNA, cell membrane, ribosomes, and membrane-bound</span>
Answer:
The Earth is essentially a closed system; it obtains lots of energy from the Sun but the exchange of matter with the outside is almost zero. Isolated systems can exchange neither energy nor matter with an outside system.
The Precambrian was originally defined as the era that predated the emergence of life in the Cambrian Period. It is now known, however, that life on Earth began by the early Archean and that fossilized organisms became more and more abundant throughout Precambrian time.
