Hi , i am preparing for data scientist and want to know why apache spark certification has become so popular among data scientists. As i was doing some research work i came to know some interesting facts about spark i.e apache Spark is a lightning-fast unified analytics engine for big data and machine learning. It was originally developed at UC Berkeley in 2009. Since its release, Apache Spark, the unified analytics engine, has seen rapid adoption by enterprises across a wide range of industries. Internet powerhouses such as Netflix, Yahoo, and eBay have deployed Spark at massive scale, collectively processing multiple petabytes of data on clusters of over 8,000 nodes. I want to have some spark interview questions also so , please guide me on this topic.