What percentage of the Earth's crust by mass is composed of oxygen (in $\%$)?

Which of the following is a mineral of copper?

Which metal is found in the Khetri region of Rajasthan?

Match List-$I$ with List-$II$.

List-$I$ (Ore)	List-$II$ (Element Present)
$a$. Kernite	$i$. Tin
$b$. Cassiterite	$ii$. Boron
$c$. Calamine	$iii$. Fluorine
$d$. Cryolite	$iv$. Zinc

Choose the most appropriate answer from the options given below.

Which one of the following is a mineral of iron?

Select the correct option using $T$ (true) or $F$ (false) for the following statements:
$(1)$ Calamine and Siderite are carbonate ores.
$(2)$ Zinc blende and Pyrite are sulphide ores.
$(3)$ Haematite and Magnetite are hydroxide ores.
$(4)$ Malachite and Cuprite are copper ores.