AQA A Level Biology复习笔记7.3.1 Genetic Variation
Genetic Variation Phenotype variation The observable characteristics of an organism are its phenotype Phenotypic variation is the difference in phenotypes between organisms of the same speci...
Edexcel IGCSE Maths复习笔记 1.7.2 Percentage Increases & Decreases
Edexcel IGCSE Maths复习笔记 1.7.2 Percentage Increases & Decreases How do I increase or decrease by a percentage? Identify “before” & “after” quantities Find percentage of “before” that we ...
AQA A Level Biology复习笔记7.2.1 Populations
Species Exist in Populations A species can be defined as a group of similar organisms that can reproduce to give fertile offspring Organisms of the same species have the same number of chromosomes ...
AQA A Level Biology复习笔记7.1.1 Key Terms in Genetics
Key Terms in Genetics Genes & alleles The DNA contained within chromosomes is essential for cell survival Every chromosome consists of a long DNA molecule which codes for several differe...
AQA A Level Biology复习笔记6.4.1 Principles of Homeostasis
Homeostasis In order to function properly and efficiently, organisms have different control systems that ensure their internal conditions are kept relatively constant Physiological control systems ...
Edexcel IGCSE Maths 复习笔记 1.7.1 Basic Percentages
Edexcel IGCSE Maths复习笔记 1.7.1 Basic Percentages What is a percentage? “Per-cent” simply means “ ÷ 100” (or “out of 100”) You can think of a percentage as a standardised way of expressing a frac...
AQA A Level Biology复习笔记6.3.1 Muscle Pairs
Muscle Pairs The effective movement of the human body requires both muscle and an incompressible skeleton This is because muscles will only produce effective movement if they pull on a structure th...
AQA A Level Biology复习笔记6.2.1 Neurones
Myelinated Motor Neurones Information is sent through the nervous system as nerve impulses – electrical signals that pass along nerve cells known as neurones A bundle of neurones is known as a nerv...
AQA A Level Biology复习笔记6.1.1 Survival & Response
Responding to Change Aids Survival Organisms must respond to changes in their environment in order to survive They can only survive if they are successful at: Finding favourable conditions for livi...
