<span>Alright.. this is what I have in mind... then you can judge if I'm totally crazy:
As in any other experiment we wish to only hold 1 variable, while other thinkable variables are held constant.
In addtion to that we need to ref. soil and call that 0.
Now some theory: We know from medicals they can have synergetic effect if mixed. Same can go for nutrients, we therefor test each soil mixed and alone and see the effect.
We call the nutrients A, B and C, (continue with more if you like)
Now this is our setups:
0, A, B, C, AB, AC, BC, ABC.
In this way we can make compare to a ref soil (0) and also check for synergetic effects... this is a bit considered a multivariable experiment, but we also have A, B and C as ref. against the mixed soils.</span>
The biggest design innovation that SpaceX has pioneered is, of course, the fact that Dragon 2 is partially reusable, potentially resulting in a significant cost reduction. The first stage of the spacecraft is capable of re-entering the atmosphere and landing vertically after separating from the second stage.
Answer:
Most texans live in cities and suburbs.
Explanation:
North America and Africa. North America’s life expectancy is around 76 for males and 81 for females. African life expectancy is around 61 for males and 65 for females