Questions

A bubble is what lighter than air but a hundred people cannot lift me.

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.

A cytoskeleton is the frame that gives shape to a cell. And also it offers support, and facilitates movement through three main components:

microfilaments,

intermediate filaments, and

microtubules.

The cytoskeleton helps the cell move in its environment and controls the movement of all of the cell's interior workings.

Two passengers behind the operator is safe for a PWC.