Select two central ideas of the passage?
A. Jacques Cousteau promoted the conservation of our oceans.
B. Over the centuries, many people have invented devices similar to the Aqua-Lung to assist divers.
C. The Aqua-Lung differs from Le Prieur’s SCUBA in one important way.
D. The Aqua-Lung allowed longer, safer dives.
E. Cousteau and Gagnan might not deserve all the credit for inventing the Aqua-Lung.
F. Aqua-Lung is still a brand of equipment sold today.
G. Cousteau and Gagnan built upon previous technologies when creating their Aqua-Lung.