Why am I all of a sudden seeing unwanted ads which I ignore, and am asked to picture verify my being a human to answer questions?

Ads = revenue for Verizon, which encourages them to keep YA up and running. When this site doesn't make money, they'll shut it down.

MANY have asked about the captchas here already. The captcha is a security measure that began on 5/27/19, to prove you are a human user and not a bot program attempting to use the site. Apparently Verizon Media chose to hire the services of Google to provide that function (as noted by the text at the bottom right of the pages “This site is protected by reCAPTCHA and the GooglePrivacy Policy and Terms of Service apply.”), instead of programming it themselves. We’re still seeing some bot posts (i.e., the Yahoo Helpline bots) because the captcha isn’t activated every time an account posts. Hopefully the captcha's will be required less frequently, soon. Otherwise, I see another migration of users away from the site due to the added annoyance.

Any time you have an issue with the site or something changes, scroll through the Yahoo Products>Yahoo Answers subcategory and see if anyone else has posted about it. You can find your answer and save yourself 5 pts a lot of times. That’s what the site was designed for (so users wouldn’t need to re-post questions that had already been asked and answered multiple times)

I haven't seen since yesterday

To Prove that you are a Human being and Not a Bot something new that Yahoo is Testing out Yahoo is trying to Control Spam and Bots and such Its not just you thats seeing them a lot of Other Users are starting to see it come up

It is a new anti-spam measure intended to fight spam on the site.

The ads are how Yahoo pays for its service. That is why they are there.

Use Adblock Plus to hide the ads: https://adblockplus.org/

Don't know but I have had them since yesterday but at the bottom of the Yahoo answers there is a Google section with Terms and Conditions all about it but I don't even have a Google account?