Are Long Life Spans in the Old Testament Plausible?

While not “proof” in the laboratory sense, the following web site provides 5 reasons why it is reasonable to believe the long life spans in the Bible are plausible.
You can read the article for the details, but the 5 reasons are:

1.Reactive Oxygen Species (ROS)
Discoveries in ROS suggest that one way God could have designed humanity to live for 900 years and then acted to decrease man's life expectancy at the time of the Flood would be to make subtle changes in the level of SOD and catalase enzyme expression within cells.

2. Caloric Restriction
Through a vegetarian diet, God could have used caloric restriction to help extend pre-Flood life spans.

3. Telomere Loss
God could have changed human life expectancy simply by varying telomerase activity. Alternatively, God may have complemented an increase in radiation levels (via a supernova event ) with a reduction in telomerase activity so as to minimize human suffering in the context of shortened life expectancy.

4. Genome Size
Larger genome sizes correlate with longer life spans. The human genome has a large amount of non-coding DNA. The non-coding DNA may have performed a critical function at one time to extend lifespans.

5. Vela Supernova
Radiation from the Vela supernova bathed the Earth and affected life expectancy. Moreover, a significant radiation event such as Vela would explain the mathematical curve, the gradual, exponential reduction in life spans, from about 900 to 120 years reported in Genesis 11.

Why are these reasons plausible? Because the scientists engaged in age research are trying to find ways to counter-act the above. If humans with their limited knowledge and power can alter life spans, how much more so can God who is unlimited in knowledge and power?