Questions

Nutrients are necessary for break down the food and supply energy to the organisms and to carry out essential life functions.

• Important nutrients are Hydrogen, Carbon and Oxygen.

• Some more important nutrients for plants are : Potassium, Sulphur, Nitrogen, Phosphorous, Calcium and Magnesium. 

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. 

Ecology is the branch of science which deals with the study of Ecosystem (relation between the Organisms and their Environment.)

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.