Explanation:

The BCG matrix is based on Industry growth rate and relative market share. BCG matrix is a framework created by Boston Consulting Group to evaluate the strategic position of the business brand portfolio and its potential. 

BCG matrix is a framework created by Boston Consulting Group to evaluate the strategic position of the business brand portfolio and its potential. It classifies business portfolio into four categories based on industry attractiveness (growth rate of that industry) and competitive position (relative market share). These two dimensions reveal likely profitability of the business portfolio in terms of cash needed to support that unit and cash generated by it. The general purpose of the analysis is to help understand, which brands the firm should invest in and which ones should be divested.
High market growth rate means higher earnings and sometimes profits but it also consumes lots of cash, which is used as investment to stimulate further growth. Therefore, business units that operate in rapid growth industries are cash users and are worth investing in only when they are expected to grow or maintain market share in the future.