Membranes are barriers and “gatekeepers”, they only let certain molecules pass through them.
they also transport nutrients to the cell
Answer: Heat causes surrounding air to rapidly expand and vibrate, which creates the pealing thunder we hear a short time after seeing a lightning flash.
Answer:
because iron is magnetic and sand is not
Explanation:
Answer: 2 kg/L or 2 g/mL
Explanation:
litres are a cubic measure. “Cubic litres” is redundant at best, potentially confusing.
