In some circumstances, when two different carbon sources are available, growth will occur first using one carbon source, then after a short lag period, growth will resume using the second carbon growth source.
a. This process is called growth.

Diauxic growth

Explanation:

The diauxic growth or diphasic growth is a bacterial growth which is characterized by the growth in two phases depending upon the source of carbon used.

The preferred carbon source is consumed first, this leads to enhance the growth in the bacteria, followed by the lag phase. During the process of lag phase the bacteria start to metabolize the second carbon source and the growth resumes.

For example, a colony of E.coli bacteria was cultured in a medium containing the glucose, and lactose sugars. At the initial level the bacteria was capable of using the glucose sugar and growth became rapid this is followed by a lag phase. In the lag phase the bacteria started to utilize the lactose sugar and again the growth resumes.

c. heat from the poles back down towards the equator.