i think answer D( convection currents in liquid iron in the outer core generate an electric current , which produces a magnetic field)
Answer:
Option D, Gastric Juices
Explanation:
The second line of defense is a non specific defense mechanism in which no specific individual is targeted but all invaders are killed in general way. Some common mode of second line of defense are - Phagocytic cells (white blood cells), inflammatory responses, macrophage system etc. The second line of defense comes into action when the invader has surpassed the first line of defense which include either physical barrier like skin, mucous membrane, hair, cilia etc. or chemical barriers like gastric juices, saliva, Hyaluronic acid etc.
Hence, gastric juice does not belong to second line of defense.
Thus, option D is correct.
Answer:
Because the leading strand is synthesized continuously while the lagging strand is discontinuously synthesized.
Explanation:
Two DNA strands have opposite polarity, that is, the 5' end of one strand lies opposite to the 3' end of the other strand. However, DNA replication can occur in 5' to 3' direction only since the formation of phosphodiester bonds require the presence of nucleophile 3' OH to attack the 5' phosphate of an incoming deoxyribonucleotide.
The problem is solved by the synthesis of the leading strand continuously and the synthesis of the lagging strand in a discontinuous manner. Lagging strand synthesis requires the formation of primers and their elongation to form Okazaki fragments that may have few hundreds to few thousands of nucleotides. Removal of primers from Okazaki fragments is followed by joining them together to make the long lagging strand. The discontinuous replication of the lagging strand makes the replication at the leading strand ahead of it.
The cellular components of blood are : B. RBC , WBC, and platelets
RBC/ Red blood cells : Responsible in delivering oxygen
WBC / white blood cells : Responsible in maintaining immune system
Platelets : Prevent Bleeding
hope this helps