The first one is reliability. I would answer it like this:
Referring to one Qualitative Characteristic, explain why the asset must be shown in the Balance sheet at its carrying value.
1. Relevance (I)
2. All financial information relevant to making decisions as to the allocation of scarce resources should be included in accounting reports. (D)
3. The carrying value has predictive relevance as represents the unallocated cost of the asset, and so it should be reported as such in the balance sheet. (L)
You could go on further but that's the general idea.
Second one is reporting period, like this:
Referring to one accounting principle, explain why it is necessary to depreciate non-current assets.
1. Reporting period (I)
2. The life of the business is divided into arbitrary reporting periods. (D)
3. To accurately calculate profit, revenues earned in the period must be matched with expenses incurred. The cost of non-current assets must therefore be allocated across their useful life. (L)
Again, you could write more but that's the general idea. You want to mention the arbitrary reporting periods and the matching rev/exps for these types of questions (typically BDAs).