Answer:
A. The cell cycle
Step-by-step explanation:
The process that is not being appropriately regulated in lung cancer cells, allowing for uncontrolled cell growth, is the cell cycle (Option A).
The cell cycle is the series of events that take place in a cell leading to its division and duplication (replication). These events can be divided into two main stages: interphase (G1, S, G2) and the mitotic phase (M).
In normal cells, the cell cycle is tightly regulated by a variety of mechanisms that ensure that cells divide only when necessary and that DNA is replicated and divided accurately. Cancer cells, however, lose this regulation, and they can divide and replicate uncontrollably. This uncontrolled cell growth is a key feature of cancer.
Fertilization, meiosis, and respiration are not related to cell growth regulation. Fertilization is the fusion of male and female gametes to form a zygote. Meiosis is the process of cell division that leads to the formation of haploid cells. Respiration is the metabolic process by which cells convert nutrients into energy.