If Mars’s atmosphere were 100% oxygen, would that make it like Earth’s? Yes; Earth’s atmosphere is mostly oxygen.
Yes; the amount of oxygen in Earth’s atmosphere changes.
No; Earth’s atmosphere is mostly nitrogen.
No; Earth’s atmosphere is all carbon dioxide.

Which type of substance ionizes partially and gives off hydrogen ions when dissolved in water? a. strong acid b. strong base c. weak acid d. weak base

Avariable that is not being directly tested during an experiment should be changed varied experimented controlled

What will most likely happen in the absence of a cell membrane? a) photosynthesis will not take place. b) the cell will not store food, water, nutrients, and waste. c) energy will not be released during cellular respiration. d) substances will pass in and out of the cell in an uncontrolled manner.