I am the respiratory substrate. I am oxidised during respiration. Who am I ?

I am a respiratory gas. I can turn the lime water milky. Who am I ?

I am a phytohormone. I am in gaseous state. I am helpful in ripening of fruit. Who am I ?

I am an alkaloid. I am present in root. I am used in the treatment of snake bite. Who am I ?

I am known as "energy currency " Who am I ?

I am cooked on steam. Who am I?

I am an indicator . I am used to detect the presence of oxygen . Who am I ?

I am a phytohormone. I am helpful in reducing waterloss in plants. Who am I ?

I am the mode of respiration in unicellular , Hydra and planarians . Who am I ?

I am a flap like structure , arresting the entry of food into respiratory tract. Who am I ?

I am a type of respiratory system present in most of the arthropods like grasshopper and cockroach . Who am I ?