Backlinks are links from other websites that point back to a website. Backlinks are important for SEO because some search engines, especially Google, will give more credit to websites that have a good number of quality backlinks, and consider those websites more relevant than others in their results pages for a search query.

No. Getting backlinks from spammy websites or unrelated-to-your-business websites will not help you but most probably will harm your rankings.

The main categories are two (2)
* Do-follow backlinks
* No-Follow backlinks

These are a number of educational links meaning that are links coming and provided from official educational institutions i.e. universities. These links have more value than the regular .com .gr .co .nl

These refer to a number of government links. Thus, links come from NGOs or governmental institutions. These links have more value than the regular .com .gr .co .nl

The number of links that are do-follow. DoFollow backlinks carry all the SEO value

The opposite is no-follow-links

If you don’t explicitly set your link as a no-follow then it will be do-follow. Therefore, the default is do-follow

Links that are inside an image. These links have less value than the regular editorial link

The number of links that are nofollow. NoFollow backlinks carry zero SEO value, however, it is advised to keep a healthy dofollow/nofollow ratio.
NoFollow backlinks are still valuable as they may not carry SEO value but they can result in getting you traffic which is also very important for your business.
On September 10, 2019, Google announced a big change. Instead of ignoring links that were deemed nofollow, Google will now start to view nofollow links as “hints.” The search engine can use this hint to determine whether or not the link should be followed and considered in the page’s ability to rank.
Well known sites are giving nofollow links as below:
* Wikipedia
* Twitter
* Quora

a) Number of external pages that redirect to a target page
b) Redirects of backlinks have more value than redirecting regular internal links

Domain Rating demonstrates the strength and authority of a target domain. It’s used in SEO Terminology
This is a number between 1 – 100 that is calculated based on links in a logarithmic scale

Internal links connect the content of a website and give Google an idea of the structure of your website. Internal linking apart from reducing the bounce rate also boost your page’s concreteness by providing valuable information.

You can simply practice internal linking by adding links inside your blog posts directing to other blogposts or pages inside your website

No, you don’t need to use UTMs. It will confuse analytics and it will create a lot of “noise”