Answer: The main function of mitochondria is to produce energy for the cell. Cells use a special molecule for energy called ATP.
Explanation: The most prominent roles of mitochondria are to produce the energy currency of the cell, ATP (i.e., phosphorylation of ADP), through respiration, and to regulate cellular metabolism. The central set of reactions involved in ATP production are collectively known as the citric acid cycle, or the Krebs cycle.
A gut with 4 stomachs would be the one. This is often found in animals that feed on grass and other plants and need 4 stomachs to be able to process the food.
Answer:
The addition of new bone tissue is termed as bone remodeling. In the process of bone remodeling, the tissues of the bone are withdrawn or resorbed from the skeleton and the formation of new bone tissue takes place also known as ossification. The mentioned procedures also monitor the shape of the bones after the incidents like fractures.
In the process of bone remodeling, two types of cells play an essential part, that is, osteoblast that generates new bone and osteoclasts that dissociates a bone. In the process of bone remodeling, the resorption of the bone takes place by osteoclasts, which is succeeded by bone deposition by osteoblasts. In combination, the cells, which are accountable for bone remodeling are called BMU or basic metacellular unit.
I think it might be the third option but I’m not sure