How is Natural selection a mechanism?

Because it is the genes that do increase the rate of survival that are passed on. It is a feedback loop that increases the rate of survival over time.

However, we can ask someone what their favorite color is and then measure the wavelength of light for that color. This gives us an objective measure of what they say is their favorite color.We also know that the experience of color is governed by the physical brain.

If energy is added to a system then you can have entropy reversal (i.e. negative entropy). This is why we are able to use things like refrigerators which produce negative entropy. If refrigerators don't violate the laws of physics, then neither does life.

Or, how do they think babies develop from a single cell? They claim that evolution of complex multicellular from single celled ancestors violates the 2nd law of thermodynamics, yet those very same people started out as a single cell and developed into a complex multicellular human in just 9 months. If it happens over the span of 9 months all of the freaking time, then they really can't say that it couldn't have occurred over the span of billions of years.

You can't intelligently design something to violate the laws of physics. Have you not heard of photosynthesis? The production of sugars from water and carbon dioxide requires negative entropy, and that is driven by the energy coming from the Sun. Yes. The equator of Mars is warmer than the poles. Any time you have a continuous temperature gradient that is negative entropy, and in the case of the temperature distributions on Mars that negative entropy is driven by the Sun (as it is on Earth). Take a look at high and low pressure systems in Earth's atmosphere. Those are driven by the Sun.

It is also possible that homosexuality is a somewhat rare side effect of another attribute that is being selected for, such as group empathy, heterosexual sex drive, or intelligence. As long as the side effect remains low then the much more common effect that is being selected for will continue to maintain the attribute in the population.

That has more to do with quantum mechanics than thermodynamics. As far as thermodynamics goes, if you dropped the egg into a bowl, and then lifted the bowl back to the height the egg was previously at you will have moved the system back to the entropy it had before. The energy used up in the system was the gravitational energy released during the fall.

I don't think there are specific mutations that are directly linked to homosexuality, but there rarely are for complex characteristics or behaviors. I would view sexuality as more of a spectrum and the result of many, many genes interacting, along with social interaction.What we may also be ignoring is the nurture side of the equation. Higher population density may trigger different types of social and emotional development. A good example can be found in some insect species, such as high population density turning grasshoppers into swarming locusts that includes obvious morphological changes. Homosexuality may actually serve a positive role when population densities get high by reducing competition for mates while maintaining kin selection.Of course, what we ought to do is not determined by what is being selected for or against, otherwise known as the Is/Ought problem.