The official leader of the u. s. senate is the
a. president pro-tempore.
b. speaker of the senate.
c. vice president of the united states.
d. senate majority leader.

The official leader of the US Senate is the President of the United States Senate - but this isn't one of the options.

However, this office is always held by the Vice President of the United States: that's why the correct answer is c.Vice President of the United States.

And in practice, this function is performed by the President Pro-Tempore (but this is not the correct answer, the president Pro-Tempore is only representing the Vice-President)

White dwarf is very hot, but also very small and that is why it may appear dim.

Early 18th century british industries were generally small scale and relatively unsophisticated. most textile production, for example, was centred on small workshops or in the homes of spinners, weavers and dyers: a literal ‘cottage industry’ that involved thousands of individual manufacturers. such small-scale production was also a feature of most other industries, with different regions specialising in different products: metal production in the midlands, for example, and coal mining in the north-east.two illustrations of 18t