Questions

In the above given sentences, only option C) The hen has laid 10 eggs is gramatically correct.

A) Not correct - We had gone to the party last night

Correct - We went to the party last night

B) Not correct - I have seen him yesterday

Correct - I saw him yesterday (We do not use the present perfect tense with past time expressions.)

D) Not correct - She is sleeping for 2 hours

Correct - She has been sleeping for two hours. (We use the present perfect continuous tense to show duration.)

Deoxyribonucleic acid (DNA) is a nucleic acid polymer composed of monomers called nucleotides. Nucleotides are composed of three components: (1) a pentose sugar; (2) a nitrogenous base; and (3) one to three phosphate groups.

Phoebus Levene, a Russian biochemist was the first to discover the nucleotide and the first to correctly identify the way nucleic acid molecules, DNA.

World day against Child Labour was launched by International Labour Organisation on 12 june 2013.Main objectiveof this year is "Say no to child labour in domestic work"

An organelle called Eyespot allows some protists to detect light. It allows the cells to sense light direction and intensity and respond to it by swimming either towards the light (positive phototaxis) or away from the light (negative phototaxis).

Eyespot is a photoreceptive organelle found in the flagellate or (motile) cells of green algae and other unicellular photosynthetic organisms such as euglenids.

Eyespot-mediated light perception helps the cells in finding an environment with optimal light conditions for photosynthesis. Eyespots are the simplest and most common "eyes" found in nature, composed of photoreceptors and areas of bright orange-red pigment granules.

The world’s largest tropical rainforest Amazon rain forests are called "Lungs of the Earth". It is so called because it produces 20% of the Earth's oxygen, and is also a vast carbon sink, absorbs more than 1 billion tons of atmospheric carbon which is emitted by the burning of fossil fuels annually.