What characteristics do zooplankton have that give them the ability to move and help them float?

When the chemicals iron sulfide (fes) and hydrochloric acid (hcl) are combined, bubbles appear from the mixture. 1. does the appearance of bubbles indicate a physical or chemical change? 2. why do the bubbles indicate this change? 3. what property is this?

Which change to the system wood cause the freely-moving piston to lower?

How many neutrons does an element have if its atomic number is 50 and its mass number is 166