The first is incomplete dominance (a mix of the two alleles is formed because neither one is dominant), the second is multiple alleles, and the third is codominance (both traits are equally expressed. Hope that helps :)
The term used to describe the organisms overall attempt at maintaining balance or equilibrium of it's internal environment is called Homeostasis.
Deuterostome would be my best guest since it pairs with another thing.
<span>The density, or more precisely, the volumetric mass density, of a substance is its mass per unit volume.</span>