<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>
Answer:
Explanation:
The temperature and pressure on the earth's surface is lower than that below the earth's surface. Generally, temperature and pressure increases as you move/dig down the earth's surface. This increase in temperature and pressure causes the earth's sediment (below the earth surface) to form a compact solid rock - this process is known as lithification.
Summary. Asexual reproduction involves one parent and produces offspring that are genetically identical to each other and to the parent. Sexual reproduction involves two parents and produces offspring that are genetically unique.
<span>Many sexually active american adolescents fail to avoid pregnancy because they are not educated on contraceptive methods. </span>
