What do nitrifying bacteria do! 1.remove nitrogen gas from ammonium 2.absorb nitrates through soil 3.convert ammonium to nitrates 4.release nitrogen from fossil fuels

The answer is: 3. convert ammonium to nitrates. This process is called nitrification, and is facilitated by nitrifying bacteria within an aerobic environment through the oxidation of ammonium (NH4) to first nitrite (NO2) and then to nitrate (NO3). This is very important for the nitrogen cycle in soils and also in water. Under anoxic conditions, denitrification occurs. 

genetics

Explanation:

calico cats must also inherit a gene unrelated to the X and Y chromosomes that codes for white fur. Because male cats have one X chromosome with code for black or orange and one Y chromosome with no color genes, they cannot technically be calico. About one in every 3,000 calico cats is born a male, and, unfortunately, don't live as long as female calicos due to their genetic abnormalities. XXY Syndrome renders male calicos sterile and can be the root cause of many other health problems