[Answer] 7. When Mark McGwire hit his 70 home runs in a season in 1998, who finished in the runner-up spot with 66?

Step 1 : Introduction to the question "7. When Mark McGwire hit his 70 home runs in a season in 1998, who finished in the runner-up spot with 66?"

...1. Gaylord Perry 2. Greg Pinchbeck 3. Sammy Sosa 4. Joe Niekro The right-handed Sosa hit 66 big ones in 1998 and was overshadowed by McGwire's 70 that season. Sosa also hit .308 with 198 hits.

[Ans] What organism contributes 70 to 80 percent of Earth's oxygen?

Step 1 : Introduction to the question "What organism contributes 70 to 80 percent of Earth's oxygen?"

Tiny microscopic plants are at the base of the world's marine food chain. These phytoplankton are a form of algae and they produce between 70 and 80 percent of the oxygen in our atmosphere. Good ol' pond scum, the green slick riding the waves, and even some marine seaweed beds are colonies of algae. Trees and other green plants supply oxygen and are important to Earth's ecosystem, but without marine algae, oxygen-dependent life would not survive on planet Earth. Source: Ecology.com

[Answer] What organism contributes 70 to 80 percent of Earth's oxygen?

Step 1 : Introduction to the question "What organism contributes 70 to 80 percent of Earth's oxygen?"

...Tiny microscopic plants are at the base of the world's marine food chain. These phytoplankton are a form of algae and they produce between 70 and 80 percent of the oxygen in our atmosphere. Good ol' pond scum, the green slick riding the waves, and even some marine seaweed beds are colonies of algae. Trees and other green plants supply oxygen and are important to Earth's ecosystem, but without marine algae, oxygen-dependent life would not survive on planet Earth. Source: Ecology.com