The correct answer is mitosis.
Mitosis is a part of the cell cycle and it is actually a cell division. The mother cell is divided to produce two new genetically identical daughter cells. It is important that during the mitosis is that each daughter cell gets a full set of chromosomes.
The ecosystem requires a constant input of energy because energy cannot be stored. The enrgy always gets converted for supporting life in the ecosystem. Some amount of energy is also lost during this conversion. So if there is not a constant supply of energy, then the ecosystem will ultimately breakdown. In case of humans, the energy is received by consuming food. The energy of the food geets converted to the enrgy that helps a human being to complete his daily chores. So energy is being lost at every step. To regain this energy the humans have to eat food regularly. This way the humans need a constant supply of energy to survive. It is the same in the case of all living things in the ecosystem.
The number of covalent bond an element can form depends on the number of electrons it has in its outermost shell (valence electrons). Carbon has four valence electrons, therefore, it can form maximum of four covalent bonds in an organic compound.
The answer is A. <span>Solar energy is a renewable resource because it can't be used up, but oil is a nonrenewable resource because it will eventually run out.</span>
