Question

Why lag , stationary and decline phases are to be considered as growth phases?

Answer 1

In geometric growth the growth is proportional to the nutrients supply after which it declines. All the daughter cells divide by mitosis. This is also known as exponential growth. Represented by a sigmoid curve where the three phases are initial (slow initial growth), exponential  (growth increases rapidly at an exponential rate) and stationary phases (growth slows down). .
Ex; Cells growing in a culture medium