Questions

Cellular respiration is best associated with the organelle Mitochondrion.

No circular or curved motion is possible without providing the necessary centripetal force. (C) provides this and so is the answer. 

Online marketing is the exchange of products and services between the buyers and sellers on the internet.It is also known as e-marketing or internet marketing or online advertising. It may take the form of : 

a.B2C where the products are sold directly to the customers. 

b.B2B where trading networks or auction sites maybe used to reach out to the new customers and serve the existing one

c.C2C where one customer may further sell the product to another customer.

Examples of online marketing may include banner ads, blogs, social network advertisement.

The correct statement from the given options is

The AV valves are supported by chordae tendineae so that regurgitation of blood into the atria during ventricular contraction does not occur.

The two main components of air are nitrogen and oxygen. They are seperated by the fractional distillation of liquid air. Liquefied air contains liquid nitrogen and liquid oxygen. Liquid nitrogen with the lower boiling point more readily evaporates than the less volatile liquid oxygen.