The karyotype for trisomy 21 illustrates an example of a genetic mutation caused by

a) insertion.
b) inversion.
c) crossing over.
d) nondisjunction

How many species of living things are alive on earth today? more than 1,000,000 none of these answers are correct 100-500 1,000 –500,000 o 500,000 -1,000,000

The kind of fertilization found in the majority of aquatic animals is (internal or external) fertilization.

It is believed that europa, one of jupiter’s moons has an ocean beneath its surface. based on how earth’s oceans and atmosphere are believed to have formed, what can be said about europa’s supposed ocean? the arrival of in the early days of europa’s existence could have formed its ocean. it is likely that the water experienced , similar to earth. it is also possible that this water is retained beneath europa’s surface and in its atmosphere due to europa’s .