Question

to survive, what gas do we need to breathe in?
a oxygen
b carbon dioxide
c hydrogen
d nitrogen
question 2
how is this gas produced?
a in plants during photosynthesis
b in animals during respiration
c in volcanoes during eruptions
d in the oceans deep trenches

Explanation:

Oxygen is essential for human survival as it is used in cellular respiration to produce energy. Plants produce oxygen during photosynthesis, where they use sunlight, carbon dioxide, and water to make glucose and release oxygen as a by - product.

Answer:

a. Oxygen
a. In plants during photosynthesis