Answer:
air masses
Explanation:
a front forms where two air masses of different temperatures meet each other
Hope that help
A plant begin to produce its own food in the following cases:
-when the first leaves are formed
-as soon as photosynthesis starts
Even the little new seeds grown-up from the food reserves, but start making their owm food as they see sunlight
The slightest change in pH can destroy the substance or organism. The pH of a cell's interior helps regulate the cell's chemical reactions. For example, the pH of blood is 7.4, if blood falls to 6.8 or lower or 8.2 or higher, it results in death.