Fourth Amendment case law deals with three main issues: what government activities are "searches" and "seizures," what constitutes probable cause to conduct searches and seizures, and how violations of Fourth Amendment rights should be addressed. Early court decisions limited the amendment's scope to physical intrusion of property or persons, but with Katz v. United States (1967), the Supreme Court held that its protections extend to intrusions on the privacy of individuals as well as to physical locations. A warrant is needed for most search and seizure activities, but the Court has carved out a series of exceptions for consent searches, motor vehicle searches, evidence in plain view, exigent circumstances, border searches, and other situations.
In population genetics, directional selection is a mode of natural selection in which an extreme phenotype is favored over other phenotype, causing the allele frequency to shift over time in the direction of that phenotype
It serves as energy for the body the cells it helps carry out nerve ceel conduction muscle cell contraction, active transport and the production of chemical substances.
Stem cells begin to transfor into different types of cells in the human body in a process known as cell differentiation.
Cellular differentiation occurs throughout the cell development of a multi-cellular organism. It occurs when the cell changes from a simply zygote into a complex system of tissues and cell types.
Stems cells are cells which have the potential to develop into many different cell types in the body during early life and growth. Stem cells serve as internal repair system in many tissues. When stem cells divide while undergoing cell differentiation, it can either retain being a stem cell or become another type of cell like muscle cell, brain cell, or red blood cell.
