accomplish according buyer cart changed chose click combination customer depending down drop dropdown feature individual menu options price product referring select selected sku stock variants weight

Can the price be changed according to what customer chose from the drop down menu? thanks.

If you are referring to having the buyer select product options from a dropdown menu before they click Add to Cart for that product, and having the price change depending on which combination of options they selected, then you would accomplish that using our "Variants having individual price/weight/stock/SKU" feature:
http://www.e-junkie.com/ej/help.variants.htm