Which of the following describes a possible effect that an increase in carbon dioxide in the atmosphere would have on an ecosystem?

a.
animal productivity would increase because more carbon dioxide would be available for cellular respiration.

b.
plant productivity would increase because more carbon dioxide would be available for photosynthesis.

c.
all of the organisms would immediately die because carbon dioxide is poisonous to both plants and animals.

d.
plant productivity would completely stop because plants cannot use carbon dioxide for life processes.