Trichodesmium erythraeum which gives colour to Red Sea is

Trichodesmium erythrium which imparts red colour to sea water of red sea is a :-

Methyl orange gives red colour in

The metal which gives brick red colour in flame test is

Which one of the followin pair is NOT correctly matched ? Option 1 Red sea-Trichodesmium erythreum (BGA) Option 2 Red tides-Rhodymenia (Red algae) Option 3 Red snow-Chalmydomonas nivalis (Green algae) Option 4 Red rust of tea- Cephaleuros virescence (Green algae)

Methyl orange gives red colour in :

What is the reason for the colour of Red Sea ?

Methy 1 orange gives red colour in