There isn't really a significance. There are 20 "ancestral" amino-acids, while the genetic code uses triplets from 4 distinct nucleo-bases (ACGT) which yields 64 codons. Redundancy is unavoidable.

Now, why did the genetic code evolve based on triplets... that's kind of a million dollar question

However, there are significant or interesting properties and consequences of redundancy. Maybe this was the question you had in mind?

> Charcoal is the chunks of carbon that are left over when you burn something organic

that's not very accurate. "burn" means letting something react with (di)oxygen, but charcoal is made by pyrolysis, whereby wood is heated to high temperatures with no or very little oxygen

Yes, this principle should apply in nature; but at the same time this only applies to a fairly restrictive case

namely, if you take a population of organisms and put it in a new environment, at first its adaptation to this environment will improve very quickly, then it will keep making progress but slower

however, in nature you have to consider that (1) most organisms have been in their usual environments for a while so they're all in the slow adaptation phase; yet that (2) environments actually change all the time, because climate isn't perfectly stable and because the surrounding ecosystems aren't stable either (ecosystems are complex systems that are constantly disrupted by new pathogens, new species, species going extinct or becoming less/more abundant, etc., on top of natural phenomena)

So there's always adaptation, because it occurs towards a forever-moving target. In most cases, it's more accurate to consider that evolution is a perpetual thing

"genetic" here means "ancestry"

Darwin didn't know about genetics in the modern sense or about inheritance (nobody would understand much about that for another 50 years or so; Darwin's own theories on the subject were all over the place, in hindsight) but at that point scientists did know that species were related to one another. Like in the sense that cats and lynxes are related.

so it's in the sense of phylogeny, not reproduction

This result has probably more to do with protein intake than milk specifically. On average so many children eat bad diets that vegan ones are generally better off

Europe doesn't have as much space as the US and nobody wants landfills near them so for the most part miscellaneous/non-recyclable plastics are just burnt along with other kinds of trash in special facilities that are equipped to handle toxic smokes

plastic is petroleum-based so it burns pretty well and modern incinerators double as power plants

p.s. I suppose you could say it's one kind of chemical transformation...

the others have given you the answer but I just wanted to point out that your logic is absolutely correct

that's why all the ancestor-related stuff always specifies "most recent". Otherwise you'd have to enumerate all the ancestors of the ancestors every single time

yeah you either have to reduce the onions first, or not cook them at all

also, very importantly: shearing waves do not propagate in liquids (quakes create both pressure and shearing waves). you can tear a solid, such as a sheet of paper, but trying to do the same to a liquid doesn't make sense. whereas pressure waves, like sound, propagate in both solids and liquids

so it's very obvious that (at least an outer layer of) the core is liquid because it's "dark" when looked at using shearing waves

even when predation is the major effect, some individuals of a species will always also die because of a range of other causes. infections and other diseases, injury, limited food, dehydration, frost, natural disasters, etc

but yes, excess predation can make a species at risk of extinction

also of note if anyone's interested, is that 100W over 24 hours is 2.4 kWh or 8,640 kJ or 2,065 kcal

obviously the actual metabolic rate varies greatly, from around 60-70W or so during deep sleep to >1,000W during intense exercise. As well as between different people

"somewhat" related indeed

Coca Cola Co be like

https://i.kym-cdn.com/photos/images/original/001/401/347/312.jpg

The carbon in the CO2 does come from food. The oxygen comes from... well, it varies, it could be food, or water you've drunk, or O2 you've breathed and that's been converted into water.

The overall reaction is (for glucose):

⅙ C6H12O6 + O2 → CO2 + H2O

but this overall reaction actually spans a large number of molecular steps. there isn't a single step where CO2 and O2 both appear

this is a similar reaction as for the burning of wood or fossil fuels. O2 reacts with reduced carbon to form CO2

> Over the last five years, scientists have developed systems that utilize electrical stimulation to help individuals recover from the paralysis that often results from such injuries. These interventions, which have been enhanced further in combination with motor rehabilitation, have changed lives but remain largely unexplained.

no, its ~30% for either

> Baseline mean (...) score was 4.44 for the [mindfulness] group and 4.51 for the escitalopram group (...). At end point, the mean (...) score was reduced by 1.35 for [mindfulness] and 1.43 for escitalopram > > https://jamanetwork.com/journals/jamapsychiatry/article-abstract/2798510

Yes, but—such skeletal differences only amount to 2-3 BMI units or so

There are genetic differences in muscle mass as well. For instance men tend to have much more upper body (shoulders/arms) muscle mass than women, but there are similar differences between individuals too. Again this can amount to 2-3 BMI units

That's why some people have a baseline BMI of 18, whereas others will have a baseline BMI of 25. That's quite exceptional though, for most people 20-23 will be normal

Your assumption that the exhaust is high pressure is wrong

Generally, you want to design the nozzle so that the exhaust pressure matches the ambient pressure. So the exhaust is very fast, but low pressure. At least, that's the case by the time it leaves the nozzle (at the throat, it's high pressure, low speed, before undergoing controlled dilatation in the nozzle)

that article does say there's "acquired resistance" and "immune memory" in plants, though clearly with a completely mechanism compared to mammals. It's right there in the "Key Points" summary

There doesn't need to be any particular reason why they were originally classified by even- vs odd-toed

The more interesting question is why did this classification held up? Why wouldn't the number of toes change, or why would it remain odd or even when it does? It really seems that it's such a random criterion that it should have been blown up by molecular phylogeny by now

I honestly don't know the answer, but it may have to do with the fact that all odd-toed ungulates will tend to have most of the load on their central digit, whereas even-toed ungulates have two central digits that they load more or less symmetrically. in turn that completely changes how the ankle is loaded. To go from one system to the other you need to change the whole alignment and mechanics of the leg, and that could be something evolution can't easily mess with

as for how weird orcas/cetaceans are compared to the rest... evolution isn't always stable. as they adapted to life in water a lot of things have obviously been tuned. though seeing how cetacea are related to hippos we at least understand how they might have spent time in the water in the first place. same thing goes for tetrapods, they're definitely very abnormal fish. some salamanders could pass as fish if you remove the legs, the rest not so much

a common approach nowadays is called "genome-wide associations"

if for a set of individuals you have both:

• measurements for a trait of interest, and
• genotypes at all genes in the genome,

then you can assess the correlation between the genetic variation and the trait variation. Typically, you might expect that most genes will have little to no correlation with your trait, but that one of a few genes will have strong correlations with that trait

that said, correlation isn't causality, so in principle you still have to figure out exactly what this or that gene does at the molecular level, what are the consequences of its interactions with other genes, and how this ultimately impacts the trait