Multiple choice

Nucleus was first observed by A. V. Leeuwenhoek in

  1. human red blood cells

  2. sea urchin eggs

  3. salmon red blood cells

  4. orchid flowers

Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

Microscopist Antonie van Leeuwenhoek (1632–1723), observed the nucleus in the red blood cells of salmon.