Aug. 31 -- After meeting with Defense Secretary Ash Carter to talk cybersecurity, Marc Andreessen, co-founder of Andreessen Horowitz, discussed market volatility in China and Twitter's search for a new CEO with Bloomberg's Emily Chang at the Moffett Federal Airfield/NSA Ames Research Center on Friday. While some investors see dead unicorns in their dreams, famed VC Marc Andreessen remains optimistic-cautiously optimistic anyway-about high-growth tech startups.