Inner core was found to be solid after observing the motion of P waves.
Explanation:
Seismologist Inge Lehmann, studied the seismic waves of an earthquake and discovered about inner core in the mantle layer of Earth. She States that there is a boundary of discontinuity between the outer and inner core of Earth.
She studied the travel of secondary and primary waves during an earthquake and how it flows at different shells of Earth's layer which helped her in finding about the inner core of mantle. She observed that the inner core is a solid layer inside the molten layer of outer core
Answer:
Option (d).
Explanation:
DNA is the genetic material of all the organism except some viruses. DNA is composed of nitrogenous base, deoxyribose pentose sugar and the phosphate group.
DNA replicatese by semi-conservative mode of replication in which one the daughter DNA consists of one newly synthesized strand and one parental strand. This mode of replication was explained by Messelson and Sthal experiment. The cells from 15N medium are transferred to 14N medium the band of intermediate density was observed. The daughter DNA consists of one 15N DNA strand and one 14N DNA strnd. This strand undergo replication in the 14N medium. This time one low density DNA band ( contains 14N - 14N DNA strand) and one intermediate density band ( 14N-15N DNA).
Thus, the correct answer is option (d).
