Questions

Secondary pollutants include ozone, which is formed when hydrocarbons (HC) and nitrogen oxides (NOx) combine in the presence of sunlight.

Whereas Primary pollutant are those pollutants that are directly emitted from their sources, like CO2, CO, SO2 as these gases are directly emitted form burning of fossil fuels.

Acid rain, which is formed when sulfur dioxide or nitrogen oxides react with water, sulfuric acid etc.

Hence, Acidrain is a secondary air pollutant.

The sciatic nerve is a combination of common fibular and tibial. 

The sciatic nerve divides into its two branches::

1. The tibial nerve

2. The common fibular nerve

at the popliteal fossa.

The tibial nerve, which travels down the posterior compartment of the leg into the foot.

The common peroneal nerve also called the common fibular nerve, which travels down the anterior and lateral compartments of the leg into the foot.

Absence of cell division is the process that never comes in interphase.

If air contained all oxygen and no nitrogen, everything would have burnt off

A Hole.

When you are digging a hole the more you take out the soil, the igger the hole becomes.