Answer:
Oxygen levels are generally thought to have increased dramatically about 2.3 billion years ago. Photosynthesis by ancient bacteria may have produced oxygen before this time. ... In addition, early plants and algae began to release oxygen at a faster rate. Oxygen levels then showed a dramatic increase.
Explanation:
The cell nucleus is a membrane-bound structure that contains a cell's hereditary information and controls its growth and reproduction. The main function of the cell nucleus is to control gene expression and mnedite the replication of DNA during the cell cycle.
The phenotypes of snapdragons of F1 generation had pink flowers only.
Explanation:
The crossing of snapdragon with red flowers and white flowers as well led to the production of F1 offspring of hybrid quality having pink flowers only. This F1 phenotype under goes pollination and results in F2 phenotype with a ratio of 1 red, 1 white and 2 pink flower.
This is incomplete dominance as the phenotypes of parental plant, as in the white and red flowered plant reappear in the F2 generation.
Answer: A!
Explanation: All biological organisms play a part in the earth's ecosystem, but consumers get energy from eating other organisms and producers make energy on their own. Grass is a producer, a self-sustaining organism that obtains its energy from the sun. In the process, it introduces new organic substances into the food chain and plays a key role for consumers. Grass forms the basis of the food chain because of this ability.
