They're not. All birds are bipedal and are descended from bipedal dinosaurs that existed long before bipedal mammals. Those dinosaurs and their bird descendants - which are technically still dinosaurs by the way - are both classified as "theropods" due to their hip structure, which is what enabled them to become bipedal in the first place, as opposed to the "ornithischian", mostly quadropedal dinosaurs which are completely extinct.

In dinosaurs and birds, bipedalism evolved as adjustments to the hips and leg orientation. In humans, the spine also underwent significant changes to support a fully upright posture.

Yep! As a gardener, I frequently sow sweet peas and vetch (both legumes) into my lawn and unused beds to generate nitrogen. I simply let these plants decompose in place once the season is over. This is how you build healthy soil, in addition to the sporadic addition of compost.

Your second paragraph is also the basis for helminth therapy - that is, deliberate infection with helminths to tame a rampaging or dysfunctional immune system, as in autoimmune disease. Infection with certain helminths makes developing certain autoimmune diseases such as Crohn's or UC less likely, and in trials has shown to alleviate symptoms of already established autoimmune disease.

Certain orchids are impossible to cultivate. My state's (MN) flower, the Queen Lady Slipper, has notoriously resisted cultivation thus far. It rarely germinates from seed, preferring to spread vegetatively. It's thought that the conditions necessary for it's germination are very specific to its natural environment - wetlands and bogs. It also takes a decade or more to mature and flower from seed, though it can live for up to 50 years. It's such a precarious and sensitive flower that it is a state crime to destroy or uproot them. I remember my grandparents had a small colony of them growing on their property by a lake up near Nisswa when I was a kid. They surrounded it with a locked fence, with a sign that read, "It is illegal by state law to pick a lady slipper flower. Anybody caught picking this flower will be shot and then prosecuted."

One thing to consider about mushrooms is that they represent a mere fraction of a much larger subterranean organism that exists in a balance with its host substrate. Some fungi are not picky about their substrate and are thus easier to cultivate. Others require a very specific substrate and growing conditions that are not currently possibly to replicate artificially.

First you need to realize that subduction happens over periods of time that the human mind can scarcely comprehend. Hundreds of millions of years. Over periods of time this large, and under immense pressure and temperature, crustal rock that subducts can be considered to act in a ductile or plastic manner similar to the mantle it descends into. Think of soil and soil creep - if you grabbed a handful of soil you'd call it solid material, but over decades or centuries, soil acts in a fluid manner as it creeps laterally under gravity and large stationary objects sink into it. Less than 0.1% of the mantle is thought to be molten, but this is enough to allow its lithic material to act in a ductile manner.

Then you need to understand that as a plate subducts, it is not at all rapidly dissolved or rendered into magma. Some of it does convert to magma and collect in magma chambers that slowly rise due to their buoyancy, which is how you get subduction-related volcanism. Think the suite of volcanoes at the perimeter of the Pacific "Ring of Fire". The immense pressure and heat generated by the spreading and subducting Pacific plate grinding beneath more buoyant crustal plates - with the addition of water and other volatile substances from the ocean - is what generates the magma which eventually rises and produces those volcanoes. Eventually, and over the course of hundreds more millions of years, the subducting plate sinks into the asthenosphere - the uppermost region of the mantle - where it may homogenize with the surrounding lithic material. The ancient Farallon plate, which subducted under the west edge of the North American plate ~50-100 million years ago, is believed to be currently undergoing this process. The plate itself can still be detected with seismological technology.

Where cities are built on wetlands or above shallow aquifers (which historically accounts for a LOT of cities, for ease of access to water), the answer is subsidence. Soil acts like quicksand to buildings over long periods of time, if it is saturated with water. Chicago is a good modern example of this.

Ebola (or ebola hemorrhagic fever) is a zoonotic viral disease which has resurfaced multiple times in separate "spillover" events from its animal reservoir species, which likely includes bats and nonhuman primates. There's more than one ebolavirus, and multiple strains have been implicated in outbreaks, with the Zaire ebolavirus thus far being the most deadly.

Even though ebola can be transmitted from one human to another, humans are not a reservoir species for ebolavirus due to the fact that it a) does not remain indefinitely latent in the human body b) is relatively hard to transmit in that it requires direct physical exposure to infected material and c) it is very frequently fatal. This is why outbreaks have been relatively sporadic with no global spread.

No, not at all. It's very similar to influenza and other respiratory infections in that regard. It has greater risk for complications and mortality because it is a fairly novel zoonotic virus despite there being other coronaviruses that already infect humans.

Viruses which have "calling card" symptoms tend to be in the minority.

It isn't the same for all spiders. Some - like the jumping spiders - have extremely acute vision with front-facing primary eyes for images and auxillary side eyes to detect motion. Other spiders - such as tarantulas and many web weavers - are nearly blind, as they detect prey mainly through vibrations and do not require refined vision.

Mechanically, spider eyes are not like compound eyes of insects that transmit hundreds to thousands of micro-images to an immobile inner eye. They are made of single immobile lenses, with mobile retinas behind them that can shift focus to separate lens ports. This is readily apparent in certain species of spider with partially translucent exoskeletons and eye lenses, such as the magnolia green jumping spider. The two front eye lenses remain immobile, but you can see a small black retina shifting behind them. Because their lenses are immobile, the spider's field of view is very narrow, so they must turn their bodies to look around. Not all spiders are capable of such focused sight - the aforementioned tarantulas basically have a teeny tiny eyeport on the top of their bodies with rudimentary eye spots that can only detect light and some motion, but can't produce a focused image.

Generally, spiders that evolved to actively hunt down prey evolved the more sophisticated, forward-facing primary eyes, and those that adopted a more passive method of obtaining prey - like spinning a web and waiting for something to get caught - did not. The diversity of body morphology among spiders is truly mind-blowing.

Yup! Your brain sits in a bath not of blood, but a different substance called cerebrospinal fluid (CSF). It is on the "internal' side of the blood brain barrier. Nutrients and water diffuse across the blood brain barrier through very fine capillaries. Blood is too thick and "sticky" for the brain to be able to use while still performing its role. CSF itself is almost entirely water - about 99%. CSF also serves to cushion your brain and act as an immunological barrier between your brain and the rest of your body.

In addition, most organs are adversely affected by direct contact with blood. You don't want blood in your stomach or kidneys or liver either! Blood is meant to stay in your blood vessels and diffuse nutrients across various tissue barriers while the glymphatic / lymphatic systems draw metabolic and immunologic waste away to be excreted.

Yes. Absolutely. Plants harbor a myriad of microbes on and within their root tissues. Plant roots aren't simply pipes that suck up water and nutrients - they're plant-soil interfaces that enable plants to do business with soil microbes and establish communication / partnerships with them.

It's why I always recommend gardeners NOT use sterile soil mixes when starting seeds, as many "guides" insist. Plants need an active soil microbiome to thrive. It's why I have a worm bin to provide worm compost for my seedlings - worm poop is rich in soil microbes and nutrients.

Your immune system is not one thing. You have your innate immune system, which includes your primary defenses to bodily insults and injury such as coagulation and inflammation. Then there is the adaptive immune system, which is a large, interwoven, almost indescribably complex framework of different cells and tissues that respond to specific threats in a myriad of ways. Many of them are dependent on each other, but some are more removed from others.

In practical terms, a strong immune system is the result of good self care, especially adequate restful sleep. Your body replenishes its stock of circulating immune cells during sleep. Sleep deprivation induces a state of temporary immunodeficiency, which is why people who don't sleep much or sleep poorly will get sick more often and stay sick longer. It does not matter how healthy you eat or how much you exercise - sleep is the foundation of good health and without enough of it your health will crumble.

None. Wavelengths of alpha, beta, and gamma radiation are outside of the visible spectrum and thus produce no visible glow of their own.

A radioactive substance can glow if it's so radioactive it generates enough heat - known as decay heat or heat of decay - to excite atoms to give off infrared / red light, like a hot stovetop. That is the sort of radioactivity that would scramble your DNA like eggs if you got anywhere near it, though.

Toasters are one of those appliances that have barely changed over the years, and any attempts at innovation largely go ignored or forgotten.

If it ain't broke, don't fix it.