The answer is D: test possible choices and then avoid ones that are not desirable.
Prokaryotes and eukaryotes both have a plasma membrane, mitochondria, golgi apparatus, and endoplasmic reticulum in common. But, prokaryotes have cell walls, chloroplast, and larger vacuoles because they are plant cells and animals don't need chloroplast since they don't undergo photosynthesis and don't need to hold as much water in their vacuoles.
The correct answer for this question is this one: "c. J.J. Thompson." J. J. Thomson is the <span>scientist who designed an experiment that enabled the first successful detection of an individual subatomic particle. </span>J.J. Thomson<span> (Sir Joseph John Thomson, 1856-1940), who demonstrated in 1897 that "cathode rays" consisted of negatively-charged particles, later named electrons.</span>
No our galaxy does not contain any planets outside our solar system
The answer is definitely A
