Answer:One Astronomical Unit is the distance between the Earth and the Sun, this acts as a sort of a cosmic metre stick. Astronomers don't and cannot measure distances. Distances are merely inferred from what actually has been measured, such as an angle, a relative luminosity, a time period
Explanation:
Answer : The correct answer is Option D.
Explanation:
Ores are defined as natural occurring substance from which metals and another mineral are extracted.
Bauxite is primary ore of an aluminium metal. it doesn't have definite or specific chemical composition. This is because it contains mixture of hydrous aluminum oxide
, aluminum hydroxides
, insoluble materials like hematite, quartz ,geothite ,magnetite etc.
From the given options the most appropriate statement which is correct about the bauxite is 'It does not have a definite chemical composition'.
Hence, the correct option Is (D).