Answer: the movement of ions or molecules across a cell membrane into a region of higher concentration, assisted by enzymes and requiring energy.
Explanation:
Requires energy input from a cell and enables A cell to move a substance against its concentration gradient
Answer:
Explanation:
Based on the scenario being described within the question it can be said that the most likely reason for this misconception would be that the spiral galaxies looked like clouds of gas and dust through telescopes because of their distance from Earth. During that time telescopes were still not as advanced and could only see so much, nowadays they are much more advanced and these galaxies are being analyzed and understood more clearly.