Answer:
In uranium-lead dating, for instance, the radioactive decay of uranium into lead proceeds at a reliable rate. Based on the very old zircon rock from Australia we know that the Earth is at least 4.374 billion years old.
And that's how after rounding we know that earth is 4.5 years old.
Answer:
When many molecules of a simple compound join together, the product is termed a polymer and the process polymerization. The simple compounds whose molecules join together to form the polymers are called monomers. The polymer is a chain of atoms, providing a backbone, to which atoms or groups of atoms are joined.
The answer is false.
Deamination is the process (reaction) in which an amine group is removed from a molecule of amino acid. The enzymes that are involved in this reaction are called deaminases. Deamination can be used for energy(break down of amino acids), when there is too much protein intake. Amine group is converted to ammonia that is then converted to urea or uric acid in the urea cycle and at the end excreted through the urine.
In the human body, deamination occurs mostly in the liver (e.g. urea cycle), but also in the kidneys (deamination of glutamate).
<span>The answer is B. The number of stomata is more on the lower surface of the leaf. Carbon dioxide enters the leaves through the stomata. In the leaves, it is used in the photosynthesis and converted into oxygen and glucose. Since the energy of Sunlight is important for the photosynthesis, stomata must be opened during the day. So, to avoid direct Sunlight and thus cause leaves dehydration, the number of stomata is more on the lower surface of the leaf.</span>
