Technically speaking, macro is where you have an image formed on the film plane at or near life size. It is the region in which you need to start concerning yourself with the impact of magnification factor on exposure, and where you notice significant changes of angle of view with object distance.
For some time, "marketing" has tried to redefine it as life-size on a certain size print, or merely something you can put on a lens to make it appear better.
Of those images, the dandelion is only just macro (the centre is a clip of the original image), the flowers certainly are macro (they're about 0.7 times actual size on the sensor), and the mass of flowers is only macro if you call any photo taken with a macro lens a "macro photograph"
I'm planning to print the dandelion at about 30x40cm which will produce an image somewhere in the order of 15 times life size.
Fortunately, these days the mag factor calculations can be ignored (TTL metering is unaffected) and you can get away with hand holding because image stabilisation is so good.
As an example of how good image stabilisation is, here is an image taken yesterday with my 100mm macro lens. The exposure was 1/8 sec and I actually felt myself wobble during the exposure (I was crouched down, not leaning on anything to steady myself). It's not the world's greatest photo, but I was really expecting a soft blurry piece of mush.
The worst thing about macro photography is that you don't see all the imperfections in the subject until later.
Here's an example of a photo where the subject was nice and clean, but the focus is off. It is really a case where manual focus and a tripod would work wonders. Cutting the flower and bringing it inside would be even better (no wind).
However you have to be really careful cutting flowers because Murphy's law means you'll get one like this:
Ignoring the fact that the focus is all over the place without any good reason, there are black spots on the petals and more pollen scattered around than you could poke a (very small) stick at.
p.s. What edible plant is the first photo, and what flowers are the latter 2 photos?