entry requirments for A levels and combinations

Check with the school on entry requirements but imo you are more likely to need 6 to study that subject at A level.
If they accept 5 then it wont matter whether its from higher or foundation tier.

Depending on your age, then BTEC or Access is an option.

For child nursing then they want some science content so one science A level should be enough or they will accept something like health and social care.


Once you meet the criteria i..e one science if you are doing A level, then go for the two A levels you enjoy the most and will get the best grades in.
Check the entry criteria to be sure.

I would avoid three science unless you have real aptitude and like them.
Psychology has no required A levels, so to cover both of your options it would be:

1x science (Bio prob and or Chem) 1x Psych although its not required. 1 other A level you enjoy and can get a good grade in.
Do your research and find out which interests and which ones you think you could cope with.