<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>
The following structural changes occur as conducting tubes
become smaller;
- support structures change. The trachea has more hyaline cartilage
than the bronchioles
- epithelium type changes with bronchioles having ciliated
columnar cells with the trachea having tall columnar pseudostratified
- amount of smooth muscle increases as you go lower the respiratory tract
Answer:
there are 7 breeding pairs
Explanation:
A nucleotide is made up of a base, a sugar and a phosphate group.
Answer:
It's All About the Plates
Heat from the Earth's interior causes this motion to happen via convection currents in the mantle. Over a period of millions of years, this slow motion caused the single supercontinent to split into the seven continents you see today
