The author assumes that the question can be answered by applying principles of anatomy, physics and evolutionary biology. First reason he suggests is that cats are small and they have a favourable mass-surface area ratio. Next, he suggests that cats have soft tissues that absorb the shock and they land on all four limbs, dividing the shock. This is because of their body shape and its centre of gravity. He says that felines have this kind of body structure (that canines lack) because years of falling from trees etc. has evolved their body in this way.
Answer:
At 0 years, an event took place which is known as metamorphosis of igneous rock i.e., formation of igneous rocks from melted magma.
Strontium-90 is a radioactive element which undergoes beta decay to form yttrium-90. It has a half life of approximately 28 years and decay energy of 0.546 MeV. This radioactivity is used by geologist to estimate the age of the rock, fossils, meteorites etc. Other radioactive elements used by the geologists are carbon-40, potassium-40 etc.
Radiometric clock is set when the rock was formed in the past i.e., the moment when an ingenious rock was solidified from molten magma.
Firstly, the enzyme, DNA Helicase breaks the Hydrogen bonds between a specific region of the DNA molecule and unwinds the duplex DNA molecule at the targeted gene sequence site.
Then, RNA Polymerase binds at the 3` site of the gene sequence of the sense/coding strand(only one strand) that acts as the template for mRNA synthesis. RNA Polymerase then matches free nucleotides by complementary base-pairing(A-U & C=G), working in the 5`to3` direction. Hydrogen bonds then form between the complementary bases, holding the nucleotides in place. Each free adjacent nucleotide is joined at 3` ends by Condensation reactions with the other to form Phosphodiester bonds.
Once the mRNA molecule is formed, it is separated from the synthesis complex and leaves the nucleus through pores in the nuclear envelope to moves towards ribosomes for Translation.
Lastly, the DNA double helix rewinds by forming Hydrogen Bonds.