Figure: Addition polymerisation of ethene

The figure shows ethene molecules forming a chain. What is the repeating unit?
CH3−CH3\mathrm{CH_3-CH_3}CH3−CH3
[−CH=CH−]n\mathrm{[-CH=CH-]_n}[−CH=CH−]n
[−CF2−CF2−]n\mathrm{[-CF_2-CF_2-]_n}[−CF2−CF2−]n
[−CH2−CH2−]n\mathrm{[-CH_2-CH_2-]_n}[−CH2−CH2−]n
37 exam-style questions on Edexcel GCSE Chemistry 10.3 Polymers, covering 10.3.1 Addition polymerisation of alkenes, 10.3.2 Uses and properties of polymers, 10.3.3 Condensation polymers and polyesters, 10.3.4 Problems with polymers and recycling, and 10.3.5 Natural polymers: DNA, starch and proteins. Each one has a worked solution and a mark scheme showing where the marks go.