Question Discussion & Solution

The correct answer is Charles Darwin.

Explanation:

Charles Darwin:

• Darwin proposed a theory of evolution called natural selection in the year 1859.
• According to it those populations which are a better fit (reproductively fit) in an environment will be selected by nature and will survive more.
• Darwin's theory of natural selection is popularly known as 'Darwinism'.
• English naturalist Charles Darwin developed the idea of natural selection after a five-year voyage to study plants, animals, and fossils in South America and on islands in the Pacific.
• Darwin conducted a sea voyage in a sailing ship called H.M.S Beagle as a part of his experiments on the theory of evolution.
• Charles Darwin became almost universally thought of as the "Father of Evolution".
• Darwin's process of natural selection has four components:
  • Variation
  • Inheritance
  • High rate of population growth
  • Differential survival and reproduction

Thus, Charles Darwin proposed the theory of biological evolution by natural selection.

Additional Information 

Gregor Johann Mendels Theory:

• Mendel used a number of contrasting visible characters of garden peas- round/wrinkled seeds, tall/short plants, white/violet flowers, and so on.
• He took pea plants with different characteristics- a tall plant and a short plant, produced progeny from them and calculated the percentages of tall or short progeny.

William Beaumont:

• William Beaumont (November 21, 1785 – April 25, 1853) was a surgeon in the U.S. Army.
• He became known as the "Father of Gastric Physiology" following his research on human digestion.
• In 1822, an employee of the American Fur Company named Alexis St. Martin was accidentally shot.
• Dr Beaumont treated his wound but expected St. Martin to die from his injuries.
• Despite this dire prediction, St. Martin survived but with a hole in his stomach that never fully healed.
• He was hired as a handyman by Dr Beaumont to observe digestive processes.​

Ernst Haeckel:

• The great scientist Ernst Haeckel was given credit to coin and express the definition of the term “Ecology”.
• ​He was a german scientist.

Rickshaw, bus and train are the means of transport.

Mobile and radio are the means of communication, so out of the given options only letter is a mean of communication.

The correct answer is Bone-marrow.

Key Points

Red blood cell:

• Red blood cells (RBCs) are the most common type of blood cell and the vertebrate's principal means of delivering oxygen to the body tissues via blood flow through the circulatory system.
• RBC is formed in Bone Marrow.
• RBCs take up oxygen in the lungs, or in fish the gills, and release it into tissues while squeezing through the body's capillaries.
• The cytoplasm of erythrocytes is rich in hemoglobin, an iron-containing biomolecule that can bind oxygen and is responsible for the red color of the cells and the blood.
• Each human red blood cell contains approximately 270 million of these hemoglobin molecules.
• The cell membrane is composed of proteins and lipids, and this structure provides properties essential for physiological cell function such as deformability and stability while traversing the circulatory system and specifically the capillary network.

Additional Information

• Red blood cells are thus much more common than the other blood particles: there are about 4,000–11,000 white blood cells and about 150,000 - 400,000 platelets per microliter.
• Human red blood cells take on average 60 seconds to complete one cycle of circulation.
• The blood's red color is due to the spectral properties of the hemic iron ions in hemoglobin.
• Each hemoglobin molecule carries four heme groups; hemoglobin constitutes about a third of the total cell volume.
• The normal pH range of blood is between 7.35 to 7.45. This means that blood is naturally slightly alkaline or basic.

Concept:

In magnetic compass, a magnetic needle which always directs the North-South direction.

• The compass is an instrument used for navigation and orientation that indicates position relative to the geographical directions (or points).
• Typically, a diagram called a compass rose displays the directions to the north, south, east, and west on the compass face.

Elements of Earth's Magnetic Field:

• The magnitude and direction of the magnetic field of the earth at a place are completely given by certain quantities known as magnetic elements.

Explanation:

Earth has its own magnetic field whose poles are

• Magnetic North is in Geographical South pole.
• Magnetic South is in Geographical North Pole.
• A compass needle is a bar magnet with a pointed north pole. It is attracted to the magnetic south pole.
• Hence magnetic needle points in North Direction (Magnetic South). 

The correct answer is chemical energy.

Key Points

• The dry cell is a type of electric battery which is used for portable electrical devices.
• Electricity is produced through the dry cells from electrochemical energy. Hence, Option 1 is correct.
• A common dry cell is a zinc-carbon cell.
• The electrolyte is immobilized as a paste by a dry cell, with just enough humidity in it to allow current to flow.
• Like a wet cell, a dry cell can work without spilling in any direction, because there is no free liquid in it.
• The versatility makes it ideal for mobile devices.
• The first wet-cell batteries, in comparison, were usually fragile glass containers featuring lead rods sticking from an open-top.
• Hence, they required careful handling to prevent spillage.
• The dry-cell battery development made a significant advance in battery safety and portability.
• Batteries render electricity from chemical energy.
• Batteries consist of one or more different parts, or cells, which contain an electrolyte called a chemical.
• Every cell has two electrodes that are electrically conductive immersed in its electrolyte.
• The electrodes consist of different materials; one releases electrons into the electrolyte, and the other absorbs them.
• Once an electrical system is attached to the electrodes, an electrical current passes through it and supports its operation with electric power.
• The energy contained in the dry cell is therefore in the form of chemical energy.

Additional Information

• Thermal energy
  • It is also called heat energy 
  • It is produced when a rise in temperature causes atoms and molecules to move faster and collide with each other.
  • The energy that comes from the temperature of the heated substance is called thermal energy.
  • Thermal energy is energy that comes from a substance whose molecules and atoms are vibrating faster due to a temperature rise.
• In physical sciences, mechanical energy
  • It is the sum of potential energy and kinetic energy.
  • It is the macroscopic energy associated with a system.
  • The principle of conservation of mechanical energy states that if an isolated system is subject only to conservative forces, then the mechanical energy is constant.
• Nuclear power
  • It is the use of nuclear reactions to produce electricity.
  • Nuclear power can be obtained from nuclear fission, nuclear decay, and nuclear fusion reactions.
  • Presently, the vast majority of electricity from nuclear power is produced by nuclear fission of uranium and plutonium in nuclear power plants.