Critical race theory
CRT scholars think about race as an intersectional  social construct.  "Social construct" means that it comes from society's rules and not from the physical world.  For example, money is a social construct.  A piece of paper is worth money because the society agrees that it is.  For example, which continent someone's ancestors came from is a real thing.  However, whether or not that is important is a social construct.  When CRT says that race is not "biologically grounded and natural," it does not mean that human beings from different parts of Earth do not look different.  It means that the rules around looking different are made up. Instead, they think of race as an idea that makes life easier for white people by making it worse for people in other races. In legal studies, CRT says that even laws that are color blind, meaning laws that look like they are not about race, can still have racist effects. CRT focuses on intersectionality, which means that race affects other identities, for example gender and social class, to produce complicated effects on power and advantage.