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.

Cretinism is a disease caused by hypothyroidism(less thyroxine formation).The symptoms of the disease are retardation  of mental, physical and sexual developments. Potbellt, protruding tongue, dry skin etc are also indicative of this disease.

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.

Jello is a colloid, a semi-rigid structure i.e, semi-solid suspended in a liquid. When you Heat it up a bit and you'll break the protein bonds of the gelatin and it will liquefy completely and if you freeze, it becomes solid.

It is to overcome this opposite frictional force , that  we have to apply the needed force to make the body move

Kyoto protocol expired in 2012

Robert Watson Watt