• The pH of blood is mainly maintained by Kidney.

• The kidneys can regulate reabsorption of carbonic acid in the tubule.

• Blood contains large amounts of carbonic acid, a weak acid, and bicarbonate, a base. Together, they help to maintain the blood’s pH at 7.4.

Metallurgy refers to the different processes used to extract valuable pure metals from mined ores. These are the types of metallurgy

• Extractive metallurgy is the practice of removing valuable metals from an ore and refining the extracted raw metals into a purer form.

• Hydrometallurgy uses aqueous solutions to extract metals from ores ( leaching ).

• Pyrometallurgy involves high temperature processes where chemical reactions take place.

• Electrometallurgy involves metallurgical processes that take place in some form of electrolytic cell

Muhammadu Buhari has been re-elected as the president of Nigeria on 27^th February, 2019.

• He won a second term, with 56% of the vote.

• The President of Nigeria is also the commander-in-chief of the Nigerian Armed Forces.

• The President is elected in national elections which take place every four years.

Exercise SAMPIRTI is annual joint military exercise conducted between India and Bangladesh.

• A joint military Exercise SAMPRITI 2019 between India and Bangladesh will be conducted at Tangail in Bangladesh from 2^nd March to 15^th March 2019.

• It will be the eighth edition of the exercise which is hosted alternately by both countries.

• The exercise is aimed to strengthen and broaden the aspects of interoperability and cooperation between the Indian and Bangladesh Armies.

• The joint exercise between India and Bangladesh was first held in Assam in 2011.

Abhijeet Gupta won the Cannes International Open Trophy 2019 on 25^th February, 2019.

• He defeated Pier Luigi Basso of Italy in the ninth and final round.

• He won the tournament with 7.5 points.

• He was jointly in the top in Delhi International Open earlier this year.

• He is the first player to win the title of Commonwealth Chess Champion four times.

= 25+18/18²

=

= (43+3) /24 = 4624

= 25 – 7 / 7²

= 18/49 = 1849