That’s the case for most species.

As a very specific and highly functional example of critical viral proteins in other organisms, there wouldn’t be any placental mammals without viruses. https://en.m.wikipedia.org/wiki/Placenta

Mammalian placentas probably first evolved about 150 million to 200 million years ago. The protein syncytin, found in the outer barrier of the placenta (the syncytiotrophoblast) between mother and fetus, has a certain RNA signature in its genome that has led to the hypothesis that it originated from an ancient retrovirus: essentially a virus that helped pave the transition from egg-laying to live-birth.

If you want to be able to write practically anything on mobile, including ≠, ≈, ‰, ℝ etc., have a look at Unexpected keyboard. No spellcheck or autocomplete, though.

Photons have zero rest mass, right? They have mass while moving, don’t they?

Is it better than using 25 % less salt?

In a considerable part of the world. https://en.m.wikipedia.org/wiki/List_of_minimum_driving_ages

I would just add that it’s a gradient of transcription factor(s), proteins that regulate production of other proteins. Some of the regulated proteins are other thranscription factors that create finer gradients, like repeated stripes of gradients. along the initial, single gradient. This can be repeated on multiple levels so that pretty much every point of the body has unique combination of transcription factors. This combination triggers all the other proteins, including structural that create the form of the body. and of course, all this doesn’t just happen in 3D, but also changes with time. It’s complicated.

For illustration and possible direction for some particular interesting cases wrapped in a very entertaining package, I recommend this: https://www.youtube.com/watch?v=ydqReeTV_vk

I wonder why I’m being downvoted. I very much welcome discussion. If you want to tell me why I’m wrong, like that cryptochromes cannot be used in sensing magnetic field upon closer look etc., I’d be excited. Disagreement without pointing out any mistakes I did brings me nothing.

If it’s just disbelief, I would’ve preferred being asked for sources. Even wikipedia mentions some of what I wrote (https://en.m.wikipedia.org/wiki/Magnetoreception) and while I admit my source isn’t primary literature, it is a monography about senses and I would’ve made an effort to track down at least some of the original papers.

That’s a strong claim you’ve got there. It seems humans do possess some amount of magnetoreception, there’s even a suggested mechanism. It might be jammed by certain radiofrequencies, although I don’t know if they are still in use. Some other mammals have been shown to sense magnetism too. Personally, when I’m in a bed, especially a new one, I feel my rotation relative to my normal bed. It isn’t very precise and it’s difficult to test, so I can’t be entirely sure, but that’s how it feels. I don’t know about any studies relating magnetism and sleep. I know there historically were people who claimed it matters to them, but I think that unless you already know that it matter to you, it probably doesn’t. I’d say that much more important is darkness. Also, I heard people feel better with feet towards the door, but I don’t know if it’s proven in any way.

Hang on, I was under the impression nobody actually thought singularities existed, only that our current math and physics isn’t developed enough to get any reasonable results in such extreme places?

This doesn’t sound very accurate. For starters, classical mechanics fails to describe even motion of Mercury. But more importantly, uncertainty in this context means someting else in this context. And while it is true that Schrödinger’s cat is both alive and dead until observed, once observed, it’s been dead or alive all along. Same with a tree, once it is determined it has fallen, it has already made the sound and produced all the consequences some time ago. While I don’t understand quantum mechanics, I’m fairly sure the person who wrote the copypasta understands it even less than me.

Test comment, please ignore.