Which organelle is used to transport compounds throughout the cell?
A. Ribosome
B. Endoplasmic reticulum
C. Nucleus
D. Mitochondria

How many copies of genes do gametes have?

Which statements explains what the fossil records indicates? check all that apply. a) earth is 4.5 billion years old b) many organisms have become extinct c) mammals have always existed on earth d) mass extinctions have occurred several times on earth e) the amount of water on earth has decreased over time?

What is the major difference between a virus and a viroid?