D) The basic unit of structure and function in all living things
There are choices for this question namely:
a. Oil and water
b. Salt and water
c. Brass (and alloy of copper and zinc)
d. Granite (a type of rock with multicolor spots)
The correct answers are
oil and water, and
granite. Heterogenous mixtures are mixtures wherein the solutes can still be identified from each other. Homogenous mixtures are mixtures wherein solutes are completely mixed and cannot be identified. In oil and water, one can identify which is the oil and which is the water. In granite, it is a mixture of different rocks and these different materials can be identified due to the presence of multicolored spots.
To make sure we don't get germs and get sick
I think it would be C. Nasal Cavity(: