What is the superposition of strata theory?
1. that oldest layers of sediment in rock formations are found under more recent layers
2. that sedimentary rock is composed of bits of rock eroded minerals
3. that the Earth's is composed of a core, mantle, and crust
4. that rock strata has been laid down for 4.6 billion years

Sally, age 3 months, has a moist, red, vesicular rash on her cheeks, the backs of her hands, and her arms. her mother said sally was constantly trying to scratch the rash and often has difficulty sleeping. her father has a family history of allergic rhinitis and asthma. discussion questions. 1. review atrophic dermatitis from chapter 3 and discuss the pathophysiology of sally’s symptoms. 2. why is the father’s medical history significant, and what can sally expect as she grows up? 3. discuss the need to limit scratching, and describe practical methods to achieve this.