Explanation

• Structure of DNA was discovered by James Watson and Francis Crick in 1953.
• They discovered the double-helix structure of DNA using X-ray crystallography data.
• Their discovery revealed the double-helix structure of DNA, where two complementary strands are twisted together with sugar and phosphate molecules, and the nitrogenous bases (adenine, thymine, cytosine, and guanine) pair in a specific manner.

Explanation

• Sunspots were first observed telescopically in late 1610 by Thomas Harriot and Italian polymath Galileo Galilei
• Sunspots are dark areas on the Sun’s surface caused by lower temperatures and strong magnetic activity.

Explanation

 The Sun is a huge, glowing sphere of hot gas.

Most of this gas is hydrogen (about 70%) and helium (about 28%).

Carbon, nitrogen and oxygen make up 1.5% and the other 0.5% is made up of small amounts of many other elements such as neon, iron, silicon, magnesium and sulfur.

Explanation

Explanation

Suspended particulate matter is a microscopic particle of solid or liquid matter suspended in the air.

Explanation

Personality plays a major role in how an individual reacts to stress.

Different personality traits, such as resilience, optimism, or neuroticism, can significantly influence how a person perceives and copes with stressful situations. 

Explanation

A man should take (3.7 liters) a day, this includes fluids from water, beverages like teas and juice, and from food.

Explanation

Oximeter is used to measure the oxygen level in blood & heart rate. 

Pulse oximeters can be attached to your fingers, forehead, nose, foot, ears or toes.

The device may then be reused or disposed of.

Explanation

B vitamins are a group of water-soluble vitamins.

Explanation

 Sound energy is a form of energy that can be heard by living beings.

Only those waves that have a frequency of 16 Hz to 20 kHz are audible to humans.