@Philip for one, more diversity when recombining the chromosome pairs. The number of genes is more or less the same, you are correct. When you have lots of genes in the same chromosomes, they usually go together into the offspring.

Also, dogs have WAY MORE chromosomes than humans. 78 vs 46 to be exact. that allows dogs to display the wide range of phenotypes they do.

99% of the atoms plants need to grow comes from the air, not the substrate (CO2, O2, H2O, N2). The substrate is needed to fix some of these nutrients but they still come from the air.

Whose observations? Are those made up? Because if you tag it as science-based, all ludicrous, made-up, or sci-fi assumptions are to be dropped.

make it so the ward infuses the material with the caster's mana, and enemies must first flush this mana, effectively discharging the ward, before they can put their own mana inside the rock. This satisfies the need to renew the wards and also makes it a war of attrition, where opposing mages fight for control over the stone — with the defenders having an advantage they can pre-load their own mana.

metalic glass, aka amorphouos metal, was invented in 1960 and require modern industrial methods.

Worse, some sites (like skeptics, stackoverflow) demand a basis in a real-life experience before a question is posted. Purely hypotheticals are frowned upon there.

1) I'm not contesting it. 2) neither this. 3) yes, but it requires a close vote 4) sure. I would like to repeat this: A Q can fit more than one Stack. But an answer in HIstory.se would be too much. For example, the suggestion by Stafish Prime would never appear there. Given the votes, many people here agree it is a good fit to solve the question's issue. e.g. creating a distinctive book cover that instantly tells the reader the book is expensive and important.

ESPECIALLY when OP is a "new contributor". Remember the principle of charity. Do not migrate questions unless you have absolute certainty the question is well-formatted for the other Stack you are dumping it to.

@Escapeddentalpatient. beware the "Q is better suited elsewhere" trap. The choice of which Stack a question is posted tells us what kind of specialists the OP wants answers from. I believe OP doesn't need historical accurate facts. Only believable ones to put in his story. Therefore, the specialists here on WB.SE are the ones he asked for help. - - - - - A Q can fit more than one Stack. That's fine. Migrating questions is a big headache most of the time.

also, I disagree with the close vote. The question IS about worldbuilding.

@Fallenspacerock yes, it was a snail, and the smell of crushed purple dye snails was heinously bad and unbearable. You got milligrams of dye out of each snail, you needed hundreds of them.

@jdunlop it is the claimant's responsibility to prove the claim. Not make affirmations based on vague "if the number is unknown, then it can be whatever I want" assumptions. The Stack Exchange guidelines demand precision and accuracy. Such fallacious claims are detrimental to the construction of a trustworthy knowledge database.

Intelligence has a genetic factor, with multiple control genes. The examples you used are akin to someone rolling 18 on all 3d6 six times. Imagine only five genes (it's more) control intelligence. If it's codependent, it means only 1:64 odds of inheriting. Each extra gene increases the odds by factors of 2 and 4 respectively. If it's recessive, 1:1024. The comparison with race horses is disingenuous.