Answer:
A) A single base pair change.
Explanation:
Point mutation is a change in a single base pair of a nucleotide. This comes as a results of mistakes made during DNA replication, induced by ultravoilet radiations, extreme heat and X-rays. There are three types of point or substitution mutations; change, deletion and insertion. The nucleotide bases are either mistakenly inserted, changed or deleted, thus changing the resulting protein or amino acid being coded for.
Answer:
1. Air warms, becomes less dense, it rises
2. Air cools down, increases density (becomes denser), it sinks
Answer:
2.7 billion
Explanation:
This period is referred to as the Great Oxygenation Event. This period saw the evolution of photosynthetic organisms (cyanobacteria) that utilized carbon dioxide (that dominated the atmosphere then) and sunlight to manufacture their energy molecules-glucose. Photosynthesis produces oxygen as a byproduct that is evolved into the atmosphere. As these photosynthetic organisms proliferated on earth, the atmosphere composition changed to become partly dominated by oxygen (which is an oxidaton agent) with less and less carbon dioxide.
Bacteria can cause many infections such as pneumonia, wound infections, bloodstream infections, and also STD's.
