Answer:
99192883829299]pppppppp??
A jet stream forms high in the upper troposphere between two air masses<span> of very different temperature. The greater the temperature difference between the air masses, the faster the wind blows in the jet stream.
</span>.
.
So "Differences in temperature between two air masses" is the answer
Answer: chromatin condenses into chromosomes and can be best observed in prophase.
Explanation: chromosomes can’t be visualised by a light microscope except during cell division (mitosis or meiosis). The individual chromosomes become visible as the chromatin is wound tightly and are most clealry seen in late prophase.
The answer 4 the above question sounds like a vitamin D deficiency.
