关于2022夏季GCSE、AS和A-Level考试成绩说明！
近日，英国资格与考试监督管理办公室（ofqual）发布最新通知：《关于2022夏季GCSE、AS和A-Level考试成绩说明》。 图源：英国政府网 1，ofqual：2022夏季考试成绩说明 1、2022年夏季考试，考试委员采用的评分方法...
IB DP Biology: HL复习笔记11.1.2 Specific Immune Response
Specific Immune Response T-Helper cells (a type of lymphocyte that responds to specific antigens) and mature B cells (another type of lymphocyte) have specific receptors located on their cell surfa...
IB DP Biology: HL复习笔记11.1.1 Antigens
Antigens Every organism has cells with unique molecules on the cell surface membrane which act as markers to identify it These unique markers are macromolecules and they allow cell-to-cell recognit...
IB DP Biology: HL复习笔记10.3.5 Skills: Comparing Allele Frequencies Between Populations
Populations & their Allele Frequencies Comparison of allele frequencies of geographically isolated populations Allele frequency is a term that assigns a relative frequency of an allele at a par...
IB DP Biology: HL复习笔记10.3.4 Polyploidy & Speciation
Polyploidy & Speciation NOS: Looking for patterns, trends and discrepancies—patterns of chromosome number in some genera can be explained by speciation due to polyploidy When patterns and trend...
IB DP Biology: HL复习笔记10.3.3 Speciation
Gradualism & Speciation Speciation can be defined as the emergence of new and distinct species that are reproductively isolated from other separate species Two theories exist to explain the eme...
IB DP Biology: HL复习笔记10.3.2 Evolution
The Process of Evolution by Natural Selection Evolution requires that allele frequencies change with time in populations Evolution is defined as the cumulative change in the heritable characteristi...
IB DP Biology: HL复习笔记10.3.1 Gene Pools
Gene Pools A gene pool consists of all the genes and their different alleles, present in an interbreeding population Some populations of the same species are geographically isolated from each other...
IB DP Biology: HL复习笔记10.2.6 Variation
Types of Variation The ways in which organisms differ from one another is called variation Variation occurs between species In fact, species are classified based on differences between their respec...
