Answer:
One
Explanation:
In a controlled experiment only one variable is changed at a time, while the others are kept the same/controlled so changes can be observed and a causation can be determined.
Answer:
Role of organisms in the nitrogen cycle:
Bacteria play a central role: Nitrogen-fixing bacteria, which convert atmospheric nitrogen to nitrates. Bacteria of decay, which convert decaying nitrogen waste to ammonia. Nitrifying bacteria, which convert ammonia to nitrates/nitrites.
Explanation:
I THINK THIS IS SHORT AND EASY
D. Cones
Cycads are basically composed of woody plants which have roots, a stem, leaves and reproductive structures called Cones. These cones differ from each other depending on the plant whether it is female or male. These cones vary from shape, size, color, etc. based on the sex of the plant.
