Answer:
Oxygen and pyruvate.
Explanation:
The krebs cycle is a stage of cellular respiration and occurs in aerobic organisms. In this case, we can say that the Krebs Cycle only occurs in the presence of oxygen, being essential for the completion of cell respiration.
The Krebs cycle only occurs after the completion of glycolysis, as it needs to be initiated by pyruvate, which is a molecule resulting from glycolysis. In this case, in addition to oxygen, the presence of pyruvate is essential for the krebs cycle to occur.
Answer:
Jean-Baptiste Lamarck
Explanation:
Jean-Baptiste Lamarck was a French biologist which developed the first theory to understand how species change (evolve) over time. This evolutionary concept was published under the name of 'Theory of the Transmutation of Species' in the early 19th century. Subsequently, Darwin published his famous and widely accepted evolutionary theory in the book 'On the Origin of Species' (1859).
Answer:
Option (2).
Explanation:
Ecological succession is the change in the ecological community of the species with respect to time. Two types of the succession are secondary succession and primary succession.
The ecological succession includes various transitional stages before reaching to the climax community. The simple species acquires first and then the climax species is reached at the end of the succession. Different changes are involved in the formation of climax community.
Thus, the correct answer is option (2).
