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.
Answer:
In grassland ecosystem, first trophic level is the producer. Producers are the organisms which makes their own food, here the producer are grasses. The second trohic level contain herbivores which feed on these grasses. These herbivores are eaten by secondary consumers which belongs to third trophic level and secondary consumers are then eaten by tertiary consumer.
The population of producers are very high so it is placed at the base while tertiary consumer are placed on the top due to low population.
Arthritis is a joint disorder involving joint inflammation.Pain is often localized to only the affected joint. Osteoarthritis is a wear and tear type of arthritis often affects aging population affecting joints in hands,knees and lower back. Heberden's node is an example and develops around middle age thus Wendell might have this.
That would be the independent variable :)