Revenue and expense data for Tribal Technologies Co, are as follows: 20Y8 2017 Sales Cost of goods sold Selling expenses Administrative expenses Income tax expense $450,000 279,000 58,500 31,500 38,250 $362,500 217,500 58,000 32,625 29,000 a. Prepare an income statement in comparative form, stating each item for both 2048 and 20Y7 as a percent of sales. Round to one decimal place. b. Comment on the significant changes disclosed by the comparative income statement