Question

The portion of sigmoid growth curve, where it represents almost a horizontal line, indicates that growth rate

• A. Slows down (lag phase)
• B. Increases very fast (exponential phase)
• C. Again slows down (senescent phase)
• D. Reduces and becomes constant (steady phase)

Answer 1

The correct option is D Reduces and becomes constant (steady phase)

Growth curve has three phases as:
Lag phase - Cell prepares for growth
Log or exponential phase - Cell actually grows
Stationary phase - Cell growth ceases.
Thus, where there is horizontal line, means the cell growth has ceased with time, represents stationary or steady phase. Hence, the correct answer is option (D).