4. Fossils
Fit of the continents
Geologic features
5. Pangaea
Answer:
Humus (hummus) is a dark organic matter in the soil which is produced by the decay of leaves or twigs (leaf litter). The litter is decayed in the soil by the action of microbial communities and chemcial reactions (together called as biogeochemical reactions). This process is also known as decomposition. The higher humus content in the soil makes it more fertile because there are more nutrients releasing due to increased turnover of the decomposing bacteria. Further, humus formation is increased if more water (moisture content) and oxygen is available.
The teacher most likely asked for additional trials because it was necessary to see data from more plants before the conclusion could be accepted.
Explanation:
- Any experiment should have multiple trials given so that accuracy of the result could be obtained.
- Repeating same experiments tests the consistency of a particular result and makes sure that the results will not be effected by random events occurring within the system or surrounding.
- Thus the conclusion becomes more precise and accurate.