Answer:
1.5 billion years ago
Explanation:
Protists are a collection formed up of protozoa, unicellular algae, and fungus forms. We will focus on the being part of this society: the protozoa (proto = first, zoa = beings). Protozoa are the earliest discovered collection of heterotrophic living that utilize and modify complicated meal particles into power. Although protozoans are only made up of a single cell, these organisms control to perform all the necessary responsibilities of life. The protozoa are split into four principal associations: the ciliates, the flagellates, the heliozoans, and the amoebas.
Answer:
Nervous system: This systems helps the five sense organs (eyes, ears, nose, tongue, skin) which all contain nerves that send messages to the brain about what is happening. The brain produces a response which it sends via other nerves to the muscles.
Digestive system: This system helps to break down food into simpler substances so it can be used and absorbed into the body. It takes place in the alimentary canal (food tube), mainly in the stomach and small intestine. The digested food is absorbed into the blood.
Respiratory System: This system helps take in oxygen and removing waste carbon dioxide. Air enters the lungs by movement of the rib muscles and diaphragm. The oxygen is absorbed into the blood.
Reproductive system: This helps produce offspring. Eggs are produces by ovaries in a female and the sperm is produced in the testes of a male. They then try and fertilise the eggs.
Note:
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