Answer: the control group was grown at a pH of 2
Explanation:
Seeds comprise a radicle, which descends and becomes the root system; the endosperm, containing stored food; an epicotyl, which develops into the stem and the seed coat that protects the seed. which are small food storage organs and plant embryos encased in a seed coat. These embryos require specific conditions in order to break their dormancy; seed dormancy is a temporary state in which plant development and growth are halted, until specific conditions required for germination to occur. Conditions required for seed germination:
- Light- some seeds require light to break their dormancy
- Oxygen- for respiration
- Water- protein hydration and enzyme activation; should be near to neutral pH
- Temperature- a specific range 20-30 °C which activates specific enzymes needed for growth
During the germination process, plants emerge from the seed and start growing. However, the delicate tissue structures can be damaged by low pH; this can occur due to acid rain, where the pH of the rainwater is lowered by the presence of pollutants.
Due to the presence of atmospheric carbon dioxide, normal rain’s pH is typically around 5.6, and in heavily polluted areas with other gases as pollutants, acid rain’s pH can range from 3-4. A highly acidic pH of 2 can denature enzymes required for germination and seed growth; apart from causing damage to the entire seed, there’s no expected growth at this pH range making it a suitable control.
Experimental controls give valuable information about the experiment’s conditions and validity; they are usually carried out in the same conditions as the other experiments, but the independent variable (pH) is usually changed.
Answer:
It lacks a nuclear membrane and resides inside the nucleus.
Explanation:
The nucleus is considered as controlling centre of the cell. The parts of the nucleus includes nucleolus, nuclear pore, chromatin, and nuclear envelope. Nucleolus is the part of the nucleus which is present inside the cell and lacks a nuclear membrane and its function is producing and assembling of ribosomes.
The reason for not considering other statement as true are as follows:
1. Nucleolus is found only in Eukaryotas.
2. Nucleus is the control centre of the cell.
3. It lacks a nuclear membrane and resides inside the nucleus.
Darwin suggested that evolution occurred through a mechanism called natural selection. This involves descent with modification, and many textbooks liken this to "survival of the fittest". Hope this helps!
When people used stone tools,
The in-between period of time when the first man appeared and when man developed a writing system. Or the period of time before man became literate.