You can start with any of these two. But i suggest you to start with BTC and give more importance to it as it's the base Crypto. Just look at the use of BTC and ETH. Both of them are famous enough. But you can never ignore the one that has created crypto.

No, Bitcoin can never be in danger as it's the father of cryptocurrency. People who don't understand the crypto will spread these kind of rumors. If you look at the historical data of BTC you'll get my point.

Many countries have already accepted Bitcoin and other cryptocurrencies. Actually the govt. who are not accepting aren't getting it's concept. As you earn more, you spend more and the country is benefited. Maybe after 5/10 years the whole world will accept Crypto as a part of their life.By that time all the govt. will understand the importance of crypto and will approve all over the world.   

People says gold is better as they consider it to be more secure than other medium of exchange. People consider gold to be real money or liquid cash. They feel like having their own money with them. Cryptocurrency and other medium of exchange may be vanished in the near future. But the use of gold will remain as long as the world is alive. It's just the belief of people that shapes this kinds of thoughts.

It's a obvious thing that Banks fear cryptocurrency as they are rival of Banks. Cryptocurrency may take over the place of banks in this world. There are many features that separates and make cryptocurrencies unique. Of course banks won't want to loose their position and vanish for good. They are trying to make people understand that crypto is totally scam and fraud.   

I think there are several reasons for the increasing price of BTC.

1.Globally acceptance, 2.easy transaction, 3.short time, 4.no transaction limit, are some of the reasons.
 
Yes, BTC has many more features that's why it's becoming popular day by day. Recently it has become so popular that it's price has just boomed. 

You see that investing in a cryptocurrency is not that you invest today and sell it tomorrow with a little bit profit. It's just like investing in a stock market that grows in the long run.
Though crypto is totally different thing, the profit that you gain from crypto can be a huge amount comparing to the stock market. All you need is just wait and watch what happen in the market. Investing a coin should be done by looking at it's historical performances. 

You got the exact point. You can write down the seeds, passwords in a offline paper or note. You can also use Hardware device to store your account details. Then you may put them in a locker in a bank for safety purposes.

World is getting modern day by day so people are looking forward for alternative ways of historical use of metal coins and paper currencies.

In  2017 bitcoin grabs the attention of the people. anonymity, easy use, no restriction etc are the biggest striking points that compels people to use it as a future high profit investment.   

Ethereum and Ripple are now very famous in CryptoCurrency. If you focus on Eth you'll see that the price of it has almost doubled comparing it was 2/3 weeks ago. So, it's clear that it's performance is very good. On the other hand Ripple has also shown a surprising peak. If you think in terms of %, of course Ripple is better than Eth.

 You don't need how much the price is. All you need is the % profit that you'll get from your investment ,right?   

Of course,ETH is going stronger. It is attracting investors very highly. Many tokens are exchanging in ETH. So, the use of ETH is broader. From the data we can easily see how ETH has quite doubled than it was just 2 weeks ago. It's going to be very high in the near future that's for sure.     

As Bitcoin is the father of crypto, it can be said that it's impossible that other coin will takeover Bitcoin.
As long as the online transaction is live crypto is live and as well as Bitcoin. Most financial researchers predict that Bitcoin will boom and it's just the beginning of the  cryptocurrency. So it's  not late to invest in Bitcoin.

It's a human nature trying to grab the best opportunity.But that doesn't mean you blindly show overconfidence and loose every thing you have.

 Yes, Bitcoin is a awesome concept.

You can invest a portion of your money in it.

As you know that investment is always risky, you can use the concept of "Portfolio". That means investing in more than one concepts.You can be a good decision.

Before investing in any coin you need to set a goal that "How long do you want to hold your investment?" Because every coin have their own concepts.One can make you profit within a few days another can after 6 months or 1 year. Look at the historical data and observe their trend line and market cap comparing to others. How fast their are growing is also important. Their ranking can another important point.

You can see Bitcoin is a burning topic now-a-days. Yes, it may be a strategy of KFC to grab attention of people by accepting BTC as a payment method. On the other hand, it will encourage other firms or companies to include BTC in their payment methods. It's no wonder that BTC price will boom, so someone must take the advantage of the opportunity. That is what KFC is doing. 

It's a true fact that saving BTC will make you rich but how long you'r gonna save it? Of-course you want to use that for your comfortable life or helping others. But there is no deadline for the growth of BTC. So,it's you who need to make a decision what you want to do  hold it or sell. But i can suggest you that it think smart "hold and sell some portion" when it grows high. 

Yes, it is possible to make 30-100 USD per day.Dear, you can see many people are offering to get 20/30 USA per day or something like that. It's not so easy to earn money without any hard work as well as you intelligence. So don't fall for the scammers. Research the market then go for it with dedication. Maybe you'll earn little in the begging, but have patience, of-course you'll be successful someday. And remember making money is never a easy task. Wish you all the best.