Tax rates in which the percentage of tax is the same regardless of the level of income is most likely a a) regressive tax. b) progressive tax. c) value-added tax. d) proportional tax.

It's D)Proportional tax

It is D, proportional tax because its the same regardless of in come

b) the planets year length would be longer

hope this !

the correct answer is the following is a list of inventions made in the medieval islamic world, especially during the "islamic golden age" (8th to 13th centuries),[1][2] as well as the late medieval period, especially in the emirate of granada and the ottoman empire.

science and technology in the islamic world adopted and preserved knowledge and technologies from contemporary and earlier civilizations, including persia, india, china, and greece-roman antiquity, while making a number of improvements and innovations.