Which could be referred to as secondary growth of stems?

Sequence how oxygen accumulated in the atmosphere and the effect it had on life by completing the flowchart

Why do mountaineers become breathless as they reach high altitudes

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?