Answer:
Excretion is the removal of material from one living thing, for example. Humans excrete tears, sweat, carbon dioxide etc.
Secretion is the movement of material from one point to another, for example. Humans secrete enzymes, hormones, saliva etc.
Basically in summary excretion is the removal of physical material and secretion is the movement of biological materials from one point to another.
I hope this was clear enough lol
DNA is made up of molecules called nucleotides. Each nucleotide contains a phosphate group, a sugar group and a nitrogen base. The four types of nitrogen bases are adenine (A), thymine (T), guanine (G) and cytosine (C). The order of these bases is what determines DNA's instructions, or genetic code. Human DNA has around 3 billion bases, and more than 99 percent of those bases are the same in all people. DNA sequencing theory is the broad body of work that attempts to lay analytical foundations for determining the order of specific nucleotides in a sequence of DNA
The respiratory and circulatory systems bring oxygen and nutrients to the cells. The respiratory and circulatory systems work together to maintain homeostasis. The respiratory system moves gases into and out of the blood. The lungs contain the bronchi, bronchioles, and alveoli.
I'd say it's an example of genetic drift.
Characteristics:
• Common in small populations.
• Alleles start being more frequent over time
Hope it heped you!