The author expresses frustration with current environmental policies, indicating a critical tone.

'Therefore' indicates a cause-and-effect relationship.

'Therefore' indicates that his preparation was a result of his studying.

The author shows an understanding attitude, recognizing the concerns of skeptics while advocating for action.

The author views education as critical for raising awareness and fostering informed action on climate change.

'Ubiquitous' means present everywhere or widespread, so 'common' is the best replacement in this context.

'Common' is the best replacement for 'ubiquitous', as it conveys the idea of smartphones being widely present in society.

'Arduous' means difficult, making option 2 the closest in meaning.

The word 'meticulous' means showing great attention to detail, which is closest in meaning to 'thorough'.

In the context of the passage, 'mitigate' means to reduce the severity of an issue, making 'reduce' the closest synonym.

'Happiness' is a noun, while the others are not.

'Under' is the preposition in the sentence.

'Under' is the preposition that shows the relationship between the cat and the table.

'Benevolent' refers to being kind and well-meaning. Hence, the synonym is 'kind'.

'Hasty' means done with excessive speed; quick.

'Meticulous' means showing great attention to detail, which is synonymous with 'thorough'.

'Vivid' means producing powerful feelings or strong, clear images in the mind, which is synonymous with 'bright'.

'Elated' means very happy or proud; therefore, the synonym is 'joyful'.

'Meticulous' means showing great attention to detail, making 'thorough' the correct synonym.

'Descend' means to go down, which is the opposite of 'ascend'.

'Contract' means to become smaller, which is the opposite of 'expand'.

'Rare' is the antonym of 'frequent', indicating something that does not happen often.

'Selfish' is the antonym of 'generous', indicating a lack of willingness to share.

'Complicated' is the opposite of 'simple'.

'Failure' is the opposite of 'success', indicating a lack of achievement.

The Berlin Wall fell on November 9, 1989, marking a significant point in the Cold War.

The First Battle of Panipat was fought in 1526, marking the beginning of the Mughal Empire in India.

The first Gulf War began on August 2, 1990.

The partition of India occurred in 1947, leading to the creation of India and Pakistan.

The Treaty on the Non-Proliferation of Nuclear Weapons (NPT) opened for signature on July 1, 1968.