I would say it is answer c.
- In gymnosperms (plants with “naked seeds”—such as conifers, cycads, and ginkgo), the ovules are not enclosed in an ovary but lie exposed on leaflike structures, the megasporophylls.
Answer:
Increased oxygen concentration
Explanation:
The evolution of O2-producing cyanobacteria that use water as terminal reductant transformed Earth's atmosphere to one suitable for the evolution of aerobic metabolism and complex life. The innovation of water oxidation freed photosynthesis to invade new environments and visibly changed the face of the Earth.
Answer:
They divide rapidly
Explanation:
Some normal cells such as hair follicles cells, mouth cells, digestive tract cells, and bone marrow cells divide rapidly. In mammalians, hair follicle cells are cells localized in the skin, specifically in the dermal layer of the skin. In this region, epidermal cells that form the root of the hair divide rapidly by interacting with neuropeptides, hormones, and immune cells. On the other hand, the bone marrow is a spongy tissue found in bones that contain stem cells (which also divide rapidly). In consequence, it is well-known that high-dose chemotherapy treatments may damage these types of cells.