Soil and rocks maybe. not too sure.
Answer:
B
Explanation:
I've had this question before got it right.
I would also say that the answer is C
Answer:
Because the English measurement system has been in use for a very long time, it will be costly and time consuming to change from the English to SI units. Many technological measurements, products, and tools were developed in English units.
The cost of converting all measurements to SI units will be costly and will require a long period of time. Conversions between the English and the SI system of units appear to be more cost-effective than hardware changes.
Example:
It will be costly to convert designs for bridges, tunnels, locomotives, automobiles, and other hardware to the SI system. Although new designs are being performed in SI units, much useful hardware based on English units still remain.
Eventually, it is likely that complete conversion from English to SI units will happen, albeit slowly.
Answer: they allow air to enter lungs and also permits air into the body
Explanation: