On 'buddy', in the UK this is considered an American term, and is used for example at universities or clubs each new student gets assigned an existing member as a 'buddy'. You could say something like "sis" for sister or "girl". Alternatively you could use "BFF" (best-friend-forever) or "best friend".Ultimately however I think your best choice is to use the gender-neutral "friend".The word "buddy" is a little archaic and was used in a time when males wouldn't have commonly referenced to females in the same way.
Christine Barter, an NSPCC senior research fellow at Bristol’s School for Policy Studies, who led the study, said: ‘Our research findings show that across Europe violence and abuse, both offline and online, in young people’s relationships constitutes a major problem yet in most countries it remains unrecognised leaving young people with little support.’ The increasing problem of revenge porn – the distribution of a private sexual image of someone without their consent and with the intention of causing them distress – is one the government has pledged to tackle with new laws.
Some countries have single-sex education models, while in others both single sex and mixed schools co-exist and it is up to the parents or the children to decide which model is preferable. I would like to ask that why first 'single-sex' is used and then 'single sex'? @Emma XL: Margaret's answer is correct in its second paragraph, but the rules of the hyphen are not loosely defined.
Among the first results that I found on the subject are the following; 1, 2. In both scenarios, the phrase is used as a compound adjective.
The rules for hyphenating compound adjectives are somewhat loose - usually, only hyphenate when clarification is needed.
A compound adjective should have hyphens when used before the noun, but it should not have hyphens when it comes after the noun.