Explain how and why you would collect the following data about a firm to assist in the preparation of its financial statements:

(a) wages paid

(b) rent paid and owing

(c) the useful life of a van

(d) level of inventory in a warehouse

(e) amount of oil in an oilwell Ij) inventory being delivered to a firm

(g) the effect of a research and development programme

(h) changes in the demand for a firm's products