A. When it comes to investment, the answer is always it depends, because different investors' situations are different.
First, if you are using an advisor to manage your investment account and that advisor charges an asset-based fee, then you are paying someone for nothing, because cash doesn't generate any return for you!
Next, if you need the cash for emergency use, or anticipates a need for a large amount of cash use, such as college expenses soon, you should put the cash in a savings account so you can gain immediate access to it.
Finally, the key question - how much cash to hold in an investment portfolio?
There is not set answer to this question - some people believe holding cash could enable you to buy bargains when they become available, so you don't have to liquidate your current holdings which might not be a opportune time to do so.
However, other people think differently, they believe cash is never a good asset for asset diversification, to manage portfolio risks, you want to hold assets moving in different directions, but cash always remains as, cash, with no return, and overtime is destined to underperform even inflation.
Other factors to consider include the size of your portfolio and your investment time horizon.