Answer:
D. service
Explanation:
Most people in the US work in jobs that require providing a service to others, whether it's at a restaurant, a department store, a school, etc. Yet, those who work in specialised jobs like agriculture, fishing, and mining are more rare because they need to live in a certain area that is optimal for such positions.
Thus, the answer is D.
Answer:
The correct answer will be option-C
Explanation:
The rhythm of the heartbeat is controlled by the pacemaker of the heart called the sino-atrial node.
The SA node generates action potentials which trigger the contraction and relaxation of the atrium and ventricles. The membrane potential generation initiates by the depolarization of the cell membrane when the L type of Ca⁺² ions opens up and calcium ions enter the cell.
This depolarizes the cell until the potential threshold is reached which lies between the -40 and -30 mV.
Thus, Option-C is the correct answer.
Answer:
The option 'All cells contain a nucleus' is not a part of the cell theory.
Explanation:
The cell theory proposed by scientists illustrates that every organism whether prokaryotic or eukaryotic is made up of a cell or different kinds of cells. It also that explains that cells are made from living things. According to the cell theory, cells are termed as the basic unit of life, without which life is not possible.
The cell theory does not claim that every cell must have a nucleus because many cells like cells of prokaryotes lack nucleus. Their genetic material is dispersed in the cytoplasm.
Answer:
Dry air is a mechanical mixture of nitrogen, oxygen, argon and several other gases in minor amounts.
Explanation: