They died, we had to barium.

There was a tundra ecosystem in Antarctica until around 12 million years ago, when it got covered in ice and became too cold to support most life. The only two flowering plants known to still survive in Antarctica are Deschampsia antarctica and Colobanthis quitensis.

Interestingly, Antarctica wasn't always at the south pole. It once had a tropical, then later a temperate climate, so there are likely some very interesting animal fossils hiding beneath the ice (assuming they weren't destroyed by repeated freeze-thaw cycles).

Eh, I don't see why you should feel bad about it. Perhaps it's not polite to discuss money so much, but if he's the one that continually brings up the subject, I don't see a good reason to hide the fact that your partner is doing well. If you speak to your partner about it, I would simply explain that your show-off friend had such a superiority complex that he goaded you into pushing back, by demonstrating to him that he's hardly the most successful person you know. Unless your partner explicitly asked you to keep her salary private, no harm done really :)

Yeah, what a Bohr

It's true that a significant part of the human genome is made up of endogenous retrovirus sequences. Retroviruses are a special type of virus that can integrate into the genome of its host (HIV is an example). In the ancient past, human ancestors were apparently exposed to a lot of retroviruses and probably many died as a result. Sometimes leftover fragments of retroviral genes got stuck in our genome, and as a result began to evolve cooperatively with our genes (or competitively, in the sense of transposons duplicating themselves).

In HIV-negative humans, there are no functional retroviruses left in our genome, so these aren't considered full viruses anymore, just leftover pieces. Some of these endogenous retroviral genes have since evolved important functions that benefit us, and viral infections were likely an important driver in generating novel, functional genes in our evolutionary history.

No, viruses aren't required for humans to stay alive. Viruses often kill the cells they infect, and at no point does the body depend on viral infection for normal development.

That said, in practice, there are some viruses that nearly every human gets exposure to, that are considered desirable to get exposed to at a young age (to avoid complications of getting exposed at a later point in time). Cytomegalovirus, for example, does not cause severe disease in young people when they are exposed, and the body has the chance to build up antigen-specific immunity, but if a woman is exposed to cytomegalovirus for the first time during pregnancy, this can have serious complications for the developing child.

Likewise, the five endemic human coronaviruses (OC43, NL63, HKU1, 229E, SARS-CoV-2), influenza A virus, varicella zoster virus (which causes chickenpox), are so widespread that there is a virtual guarantee that you will be exposed at some point during your life, therefore it is important to develop antigen-specific immunity to these (ideally by vaccination; ideally when you are young and healthy) to avoid the dangerous complications that can occur, especially if you are exposed for the first time at an older age.

At any given point in time, there are always billions of bacteriophages replicating inside you. Bacteriophages are viruses that infect bacteria and are widespread throughout the whole world. The human digestive tract is sterile at birth, but is quickly colonized in the first few days of life by bacteria that bring bacteriophages with them. Bacteriophages cannot infect human cells, so their effect is primarily on their bacterial hosts, not us directly. (Humans can survive and develop without gut bacteria if they are kept in sterile conditions, so in no way are these bacteriophages essential for human life.) Since most of the bacteria in your body is in your gut and on your skin, bacteriophages may play a role in killing some bacterial families allowing other types of bacterial families to fluorish, which could be good or bad, depending on the situation, something scientists have tried to harness to combat dangerous bacteria (with something called phage therapy).