用车不要说这个颜色的车你不爱 看过的人都会

百度 胃结石的危害远小于尿结石和胆结石，其主要症状是胃胀不适，但有些胃结石达到十几厘米时，就会压迫胃壁，引起溃疡、出血，甚至穿孔和恶变。

This is another of the series of A-level wikibooks. This book is based on the OCR and AQA A-Level Biology specifications, but is not endorsed by either exam board. It should be useful as a revision guide or to find alternative explanations to the ones in your textbook.

This book assumes that you have completed GCSE science. If there are problems with this book, in clarity or a conflict with the syllabus, please feel free to post on the discussion page or to edit it. Useful Assessment Statements for AS&A2 Biology can be found in the IB Biology page.

OCR

AS

• Biology Foundation
• Human Health and Disease
• Transport

A2

• Central Concepts

A2 (optional modules)

• Application of Genetics
• Environmental Biology
• Growth, Development and Reproduction
• Microbiology and Biotechnology
• Mammalian Physiology and Behavior

AQA

AS

• Unit 1 (BIOL1)
  • Disease and Immunology
  • The Digestive System
  • Cells
  • The Respiratory System
  • The Circulatory System
• Unit 2 (BIOL2)
  • Variation
  • DNA and Genetics
  • Variation in Biochemistry and Cells
  • The Cell Cycle and Differentiation
  • Exchange and Transport Systems
  • Classification
  • Antibiotic Resistance
  • Biodiversity
• Unit 3 (BIOL3)

A2

• Unit 4 (BIOL4)
• Unit 5 (BIOL5)
• Unit 6 (BIOL6)