Sort:  

Cryptocurrencies are very volatile. And most cryptos value go with BTC. So you are not really safer by investing in more currencies.
If your only interest is profit you could invest in smaller currencies whose changes are percental bigger (eventually more profit). But be aware from PoW currencies that have too little hashing power, so they would be vulnerable for 51%-attacks.

No it is although the most safest investment as the bitcoin , ethereum, ripple , cardano, steem sometimes, eos all of them show highest returns, although if you put 10000 dollar in all ten coins today and take out in January next year you will get 100000 dollar , its my promise and prediction .

It won't be that way. The currencies are too volatile.