Very powerful microscopes were needed before cells could be observed in detail
A lit candle needs to draw oxygen from the air in order to continue burning. If you limit the amount of air available, the candle's flame eventually goes out once it uses up all the oxygen. Lit candles in smaller jar stop burning first because the oxygen trapped in the jar are fewer than the ones in bigger jars.
d. Sea Cucumber
Sea cucumbers are filter feeder. Sea cucumbers often find places that have strong currents to find food.
