You are confusing elements - atoms - and molecules. There are indeed 92 natural elements, H to U. Each element appears as individual atoms, such as hydrogen atoms, carbon atoms, etc. These individual atoms can and do bond with each other to make molecules, such as methane CH4, water H2O, etc. I hope you are not confused anymore.
You can look it up on da internet
Answer:
They emit greenhouse gasses.
when changes in a protein appear to accumulate at a constant rate over time is called option (c) i.e, Molecular clock.
<h3>What does molecular clock mean?</h3>
The term "molecular clock" refers to a method that estimates the time in prehistory when two or more life forms diverged by analyzing the mutation rate of biomolecules. Typically, nucleotide sequences for DNA, RNA, or amino acid sequences for proteins serve as the biomolecular data for these calculations.
Hedges, a biology professor at Penn State, claims that the molecular clock counts the mutations that accumulate through time in the gene sequences of various species rather than counting seconds, minutes, and hours.
Mutation and recombination, the two fundamental biological processes that give rise to all heritable variations, are the foundation of molecular clocks. Mutations are modifications to the genetic code of DNA, for as when the nucleotide Guanine (G) turns to Thymine (T).
To know more about molecular clocks refer to: brainly.com/question/8597562
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Answer:
b. epinephrine on beta 2 receptors causes bronchodilation
Explanation:
This is because epinephrine is an hormone and neurotransmitter that stimulate beta 2 receptors which causes signaling and their in presence in airway smooth muscle causes bronchodilation, which counter the activation of the M3 muscarinic receptors in cardiovascular. When stimulate in skeletal muscles it can lead to increased contractility and also to muscle tremors.