You've done your research.

The only additional extant species I can think of are more honorable mentions. Sagittariidae are mostly terrestrial, but capable of flight and nest in trees.

Ground cuckoos in the subfamily neomorphinae also aren't truly flightless, but are terrestrial. They aren't true carnivores, but they are fierce predators and will prey on rattlesnakes and tarantula hawks.

In general the smaller the mammal the faster it's metabolic rate (with some exceptions). A faster metabolic rate generates more heat. Flight also requires a lot of effort and the metabolic rate goes quite high while animals are flying. In birds we see a typical core temperature of 102-109F and bats 99-106F.

I'm talking about requirements for the average person building muscle. It sounds like you're talking about workout intensity for a specific goal or sport. High intensity sports and higher rep weight lifting favor the fast glycolytic energy system. Low rep powerlifting and strength training favor the ATP-PC energy system, and endurance sports favor the oxidative system.

If you're playing a high intensity team sport or lifting in the higher rep ranges then supplying carbs for the glycolytic system is good for overall performance.

Fats, protein, and carbohydrates are all energy. There's no link requiring dietary carbohydrates to be THE energy source for a successful workout or building muscle. In the absence of dietary carbs your body will synthesize glucose as needed and convert fat to ketones. There are essential amino acids and essential fatty acids. There are no essential carbohydrates.

If you're the average person doing reps in a gym you'll build about the same amount of muscle regardless of carb intake assuming total calories, protein, and training routine are equal. There are freely available studies on this if you want greater detail.

You asked about spiking blood sugar while training. A normal person with normal activity level can build muscle on a zero carb diet. Muscle protein synthesis drives muscle growth. Glycogen from carbs only serve as an energy source.

I think what they're trying to say is zero calorie sweeteners can lead to weight gain. Artificial sweeteners have been used in the agriculture industry for quite some time as food additives to increase the weight of livestock.

Quoted from an animal feed ingredients producer and linked to their info: "The ultimate purpose of using sweeteners is to promote the animal’s continuous hunger, thereby increasing the total feed intake and improving the performance of animal production."

Artificial sweeteners themselves are usually zero calorie and don't directly add weight. Instead they cause a higher insulin release when you do eat something later. This can cause you to consume more simple carbs and more calories overall in order to feel satisfied.

https://pubmed.ncbi.nlm.nih.gov/27956737/

Edited to add sources and point out that we add zero calorie sweeteners to animal feed because the research is solid and we know the animals will gain more weight on them. There are no conflicts of interest. We want the animals to gain weight and the research supports using the sweeteners to accomplish that.

>Which species of dinosaurs had feathers?

It's likely all of the avian dinosaurs had feathers. Many non-avian dinosaurs are believed to have had feathers with strong evidence that some did. If you want to include filamentous pelts into the definition of feathers even more species are included. Feathers weren't exclusive to dinosaurs. Pterosaurs also had feathers.

> Did only small dinosaurs have feathers?

Yutyrannus huali is currently the largest known dinosaur with feathers. It was nearly 30 feet long and over 3000lbs. The recently extinct elephant bird stood 9 feet tall and 1600lbs.

>Are all dinosaurs birds or reptiles?

All dinosaurs are reptiles. All extant dinosaurs are birds.

Fun fact: the crocodile's closest living relatives are birds.