"<span>The genes for melanin pigmentation remain turned on and prepare more melanin than usual to protect the skin from photo-damage when it is exposed to sunlight for long time" is the actual reason. </span>
<span>Only one sperm normally fuses
with an egg because if more than one sperm fuses, through a process
called polyspermy, development of the zygote usually stops.
</span>
<span>Fertilization of one egg by
two sperm is possible, but the resulting zygote is almost never viable
because such a zygote would have three sets of chromosomes instead of
the normal two. This condition, called triploidy, is usually
incompatible with life. Those rare triploid infants that do survive to
term have severe and multiple birth defects and rarely live more than a
few days. </span>
A. Earth
Geocentic, is a theory of Ptolemy. Where the Earth is the center of the solar system.
lemon juice is 100 times as acidic as tomato juice. remember, each step in the pH scale represents a change in concentration by a factor of 10. since tomato juice has a pH of 4.0, and lemon juice has a pH of 2.0, the concentration would change by 10 times 10.
Glucose is an organic molecule.
So the correct answer is B.
Hope this helps,
Davinia.
