Photosynthesis is vital for maintaining levels of atmospheric oxygen.

This is true. Photosynthesis plays a vital role in maintaining the levels of oxygen in the atmosphere. Oxygen is a byproduct of photosynthesis

Oxygen is crucial for the survival of most terrestrial and marine animals including man.  The level of oxygen in the atmosphere is about 21%. The process of photosynthesis helps in maintaining this balance. Plants absorb carbon dioxide and produce oxygen.

Without photosynthesis , life on earth would come to a halt. The process of photosynthesis was first discovered, albeit partially, in the 1600s by Jan Baptista van Helmont

i am a little confused myself with what goes with the letters and what goes with the numbers but ill do my best to you

the cordillera states and grand canyon are along the southwest u.s. and northern mexican pacific.

the great plains and southwest desert are also the prairie and home to many earthquakes too .

the coastal plains have poor soil and many factories started in the south.

is this what u needed? if not i can see what i can do