help me answer this questions in a concise manner and please don$$t use AI$.$

$3.$ Why was it profitable for GM and Ford to integrate backward into component$-$ parts manufacturing in the past, and why are both companies now buying more of their parts from outside suppliers?

$4.$ What value creation activities should a company outsource to independent suppliers? What are the risks involved in outsourcing these activities?

$5.$ What steps would you recommend that a company take to build mutually beneficial long$-$term cooperative relationships with its suppliers?