Final answer:
A gene in Arabidopsis that is expressed at all times in all cells is likely involved in fundamental cellular processes such as cell division and senescence rather than specific processes like photosynthesis or flowering. The correct option are Option 2: Cell division. & Option 4: Senescence.
Step-by-step explanation:
If a gene in Arabidopsis is expressed at all times in all cells, there are several processes it might be involved in, as this type of ubiquitous expression suggests the gene plays a fundamental role in general cellular function. Considering this, it is unlikely that the gene is involved in specialized processes such as photosynthesis or flowering, which are highly regulated and occur in response to specific environmental cues or developmental stages. Instead, the gene would more likely be involved in essential cellular processes that are universal to the cells' survival and function.
Given this gene's constant expression, cell division appears to be a fitting process. Cell division is fundamental for the growth and maintenance of all plant tissues. Similarly, senescence is a process that occurs in all living cells eventually, and genes that are consistently expressed may play a role in the initiation of senescence or in maintaining cellular functions until senescence is triggered.
Although gene expression tends to be a complex and context-dependent phenomenon, genes that are always active typically support basal cellular functions rather than highly specialized functions that operate only under certain conditions.