Questions

Enzymes are macromolecular biological catalysts. Enzymes accelerate chemical reactions. The molecules upon which enzymes may act are called substrates and the enzyme converts the substrates into different molecules known as products.

Digboi, in Assam is where the oldest oil refinery in India. It was build in 1901.

'and made India' should be used to make the sentence grammatically correct. You use 'made' when referring to things already done in the past.'Make' is present and its continuous its still been done unlike 'made' which refers to what has been done

Activation of the receptors by stimuli is called Sensation.

Pound Sterling is the official currency of United Kingdom.

-> Renminbi is the currency of China.

-> Euro is the currency of 19 countries like Spain, Austria, Finland, Italy, Germany, Greece, Belgium, etc...

-> Dollar is the currency of United States.

While plant cells have chloroplasts to photosynthesize, they also require ATP for cellular functions, and do use oxygen to break down some of the sugar they produce in order to generate that ATP. Cellular respiration takes place in the mitochondria. They need mitochondria for this reason.
Hence with this logic, we can say that Plants cells have mitochondria.

The nervous system of the human brain consists of the central nervous system which has brain and the spinal cord and the peripheral nervous system which has perpheral, cranary, spinal nerves.