Answer:
A scientific theory is a well-substantiated explanation of some aspect of the natural world, based on a body of facts that have been repeatedly confirmed through observation and experiment. Such fact-supported theories are not "guesses" but reliable accounts of the real world.
Explanation:
Most autotrophs make their "food" through photosynthesis using the energy of the sun. Heterotrophs cannot make their own food, so they must eat or absorb it. Chemosynthesis is used to produce food using the chemical energy stored in inorganic molecules
When an ophthalmologist uses an ophthalmoscope to look into your eye he sees the following view of the retina
In the center of the retina is the optic nerve, a circular to oval white area measuring about 2 x 1.5 mm across. From the center of the optic nerve radiates the major blood vessels of the retina. Approximately 17 degrees (4.5-5 mm), or two and half disc diameters to the left of the disc, can be seen the slightly oval-shaped, blood vessel-free reddish spot, the fovea, which is at the center of the area known as the macula by ophthalmologists.
1- 4 Na + O2 —> 2 Na2O
2 - 4H2 +2O2 —-> 4H2O
3- Na2SO4 + CaCl2 —> CaSO4 + 2NaCl
4- 2Al2O3–> 4Al+ 3O2
5- N2 +3 H2–> 2 NH3
6- 3Fe +4 H20–> Fe3O4 + 4H2
I’m having trouble reading the last ones .