Answer: 1.251 billion years
Explanation: The half-life of potassium 40 is 1.251*10^9 years. Since in the igneous rock there is one half of potassium left it means only one half-life has passed.
B i know this one you got this bro
Answer:
Hyoid bone
Explanation:
It is a bone responsible for tongue movement.
A- DNA is a double stranded molecule :)
Answer:
It destroy both harmful and beneficial microbes.
Explanation:
If scientist added a chemical to destroy the arctic microbes, the beneficial as well as harmful microbes also eliminated from that area where chemical is applied. The removal of harmful microbes is a good thing but the removal of beneficial microbes brings instability in the environment. These beneficial microbes helps in the recycling of nutrients for the plants present there. So the negative effect of chemical is that it also effect the beneficial microbes which are necessary for the ecosystem.