Most acid precipitation results from the combination of with water in the atmosphere, forming strong acids that fall with rain or snow. see concept 3.

Most acid precipitation results from the combination of sulfur and nitrogen oxides with water in the atmosphere, forming strong acids that fall with rain or snow.

Acid rain has low pH because of the elevated levels of hydrogen ions. It can cause damage on plants, animals and infrastructure.  

Forming of acid rain:  

NO2 + OH• → HNO3

SO3 (g) + H2O (l) → H2SO4 (aq)

straight probes are used primarily for measuring flow as it is approaching the test area. its geometry allows the probe to be mounted so that it is in the direct line of airflow.

i think it is d. objects resist changes in their state of motion.