Questions

Normal Gas welding use oxygen-acetylene.

Depending on what materials you are welding, there are some more options that might be used.

For example - MIG/TIG use Argon, MAG use an argon-something mix.

If you were to produce a protein in bacterial cloning systems, you would not get the same post transcriptional and post translational modifications because the prokaryotic and eukaryotic systems work differently on the modifications.

Thus human recombinant protein genes are usually cloned in yeast cells. Also since they have a short generation time, they can be easily culture.

7th may is considered as world's Asthma day .This worked with the theme of "you can controll your asthma"

An up - selling is getting the customer to spend more money, buy a more expensive model of the same type of product, or add features or warranties that relate to the product viewed or purchased. 

A cross - sell is to get the customer to spend more money by adding more products from other categories than the product being viewed or purchased. 

The clotting of blood is a chain reaction initiated by the enzyme thrombokinase produced by the platelets. This causes prothrombin to be converted into thrombin in the presence of Ca++ion.

Thrombin combines with fibrinogen  to produce fibrin threads which entangles the corpuscles to form the clot.