There is a form of chemical communication that goes on. There was some research done recently where they looked at plants having their leaves pulled off, and they found that the plants scream chemicals to signal that this damage has occurred. There are a number of chemicals produced. One of them is called ethylene (H2C=CH2) and that is a signal that tells the plant that it is being damaged to grow some more. It also makes fruit ripen. Bananas produce lots of it and so can help other fruit to ripen much faster. There is also communication between plants and the fungi in the soil (a mycorrhizal relationship). Fungus is very good at extracting water and minerals from the soil, and it swaps these with a plant, which will provide it with sugars to give it energy, so both benefit. People used to think that there were two species of thistle, a dwarf and a tall thistle, but they were both the same species, just with different fungi, referred to as Hartig nets, growing around their roots.

It depends on the insect. The large ones like butterflies don't; they hide somewhere dry such as under a leaf as a raindrop would do them a lot of damage and make them much heavier. On the other hand tiny insects such as midges are so small that they will tend to get blown out of the way with the air rushing around the raindrop as it falls.

There must be a chemical in the asparagus that is absorbed into your blood through your gut, and then filtered out by your kidney into your urine. Scientists don't know what the chemical is, but it must move quickly as people can smell it in their urine after only half an hour. Interestingly some people claim not to be able to smell the difference.

Yes that is the normal process of cell division and they are made from stem cells in your thymus and bone marrow etc.

There is no reason why not. As Galileo noted, the important thing is your relative speed not the absolute one. So if the trailer is doing 60mph and the car 70mph, once the car is on the trailer it will only be doing 10mph relative to the trailer. So it would be like driving onto the trailer at 10mph. The one problem you could get is that if you don't make the transition with your foot on the clutch, the wheels will go from 70mph to 10mph while the engine is still trying to push them at 70. This will either cause a lot of burnt rubber or bits of your engine to fall out.

If you are close enough to breathe in a significant amount of the smoke from fireworks, you are too close. Most of the things in the smoke are the same as you would find in wood smoke. In Disneyland they have a large firework display every night over a lake, behind their castle. They commissioned a study to look at any pollution caused after 250 shows a year for 30 years. Even with modern techniques they couldn't actually detect any pollution, so it is probably ok.

There are some people who can memorise immense amounts and others who forget what they had for breakfast. The difference is down to your genes, we have a million million neurons in our brains and your memory works by making connections between these stronger by a process called long term potentiation. This happens in a part of the brain called the hippocampus and also the amygdala, but we don't know how memory actually works. What we do know for example, is that if you learn lots of languages, particularly from a young age, the part of the brain involved with language (the language cortex) gets bigger.

The microwave background radiation is left over from the big bang. Originally the whole universe was so hot it was a plasma and the electrons had so much energy they were wandering about separate from the nuclei. About 300 years after the big bang the universe cooled enough for the electrons to get trapped by nuclei-forming atoms. This released an immense amount of energy in the form of light.
Originally this would have been in the form of X-rays or ultra violet with a wavelength of less than a thousand trillionth of a metre. As the universe expanded, the light was stretched too, to the couple of millimetres it is on average now. Microwave background radiation is still around now because the universe is very empty and it hasn't all hit anything solid yet.

Smell molecules trigger nerve cells in your nose. These cells then connect to a structure called the olfactory tract and this links up to areas of the brain that are very close to where memories are laid down. This is in a primitive part of the brain, which controls animalistic behaviours such as emotions, sex drive and general arousal. So scientists think that smell can trigger all these other emotions. Also, memories don't seem to be laid down as a video clip, but are distributed all over your brain. So remembering something is like doing a jigsaw puzzle or a collage; the more pieces you have the easier it is to find more.

Unfortunately, blokes seem to get hairier as they get older. It's to do with testosterone - the hormone that makes us uniquely male. It makes hair grow on some parts of the body, makes your skin greasier, and makes hair fall out on the top of your head. The hairs in your nose and ears do have an important job, as they filter out large lumps of dust or fluff that would damage your lungs. Testosterone just makes them grow thicker and longer. It seems to be an exposure effect so over time we get hairier and hairier, and there is not a lot we can do about it apart from investing in a nose clipper.

Although the gene could be turned on from birth and doing damage all the time, it may take a long time for the damage to cause a major problem. For example, if you have a gene for a blood disease that creates something to block up blood vessels, it could take fifty years before it has accumulated enough to actually block them. There is another disease called Huntingdon's disease, where the gene is active from birth, and produces a protein that builds up in a cell. Like a rubbish bin, you can keep adding rubbish until eventually it overflows and causes a problem, so the disease only hits when you get to 40 or 50 years old.

Gravity is nothing to do with rotation. If the earth were a perfect sphere, gravity would be the same in all directions. As the earth is actually slightly flattened, gravity will be slightly larger at the poles. What the rocks are below you also makes a difference. If you are on a very dense piece of rock, gravity will be slightly higher. Of course, if you are interested in how much you will appear to weigh, centrifugal force will also have an effect so you will appear to weigh less than you would do if the earth wasn't spinning.