<u>Answer:</u>
Cyanobacteria start producing pure oxygen around 200 million years ago.
<u>Explanation:</u>
Many scientists believed that Earth did not have any oxygen. Cyanobacteria or the blue green algae are the microbes which produced oxygen for the first time with the help of photosynthesis. This was around 4.5 billion years ago: after Hadean eon.
They were very simple, but they produced oxygen in the early earth’s atmosphere. So, they brought evolution on earth. This “blue-green algae” exists in salt water, rocks and soils and play a major role in maintaining the ecosystem.
<h2>Primates </h2>
Explanation:
Primates are a group of animals has flexible hands and feet, large brains in relation to body size, forward-looking eyes, and arms that can rotate in a circle around the shoulder joint
- Primates include the lemurs,lorises,monkeys,apes and humans
- The order Primates, with its 300 or more species, is the third most diverse order of mammals, after rodents and bats
- The Primates order is divided informally into three main groups: prosimians, monkeys of the New World, and monkeys and apes of the Old World
- All primates have five fingers (pentadactyly), a generalized dental pattern, and a primitive body plan
- Another distinguishing feature of primates is fingernails
- Opposing thumbs are also a characteristic primate feature
- When compared with body weight, the primate brain is larger than that of other terrestrial mammals, and it has a fissure unique to primates that separates the first and second visual areas on each side of the brain
- The eyes face forward in all primates so that the eyes visual fields overlap
- Fossils of the earliest primates date to the Early Eocene Epoch (56 million to 40 million years ago) or perhaps to the Late Paleocene Epoch (59 million to 56 million years ago)
Answer:
a. Mastication process and formation of bolus in the oral cavity
b. The contraction in the stomach breaks the food down into smaller pieces. These pieces are then moved to the small intestine.
c. In the small intestine, food particles are broken down into nutrients, fat, protein and carbohydrates which are absorbed into the bloodstream.
Explanation:
a. First step of digestive system functioning is the mastication process and formation of bolus in the oral cavity.
b. The contraction in stomach, with the help of digestive enzymes and acids, break the food down into smaller pieces. The small pieces of food are then released into the first part of the small intestine (duodenum).
c. In the small intestine, two enzymes released from pancreas and gall bladder break down the food particles into fats, proteins, and carbohydrates. Thereon, nutrients and carbohydrates, proteins and fats are absorbed into the bloodstream.
Answer:
D
Explanation:
The plants in the light formed bubbles because they released oxygen gas, This is because bubbles that are formed takes the places of oxygen molecules O2. Oxygen is released during photosynthesis through the process called light-dependent reaction. The light-dependent reaction occurs only in the presencee of light. So, if bubbles formed are equivalent to oxygen molecules released in light-dependent reaction, then it is expected for bubbles to be found only on the leaves on those plants that were in a well-lit room.
What is soft layer of earth that has convection currents and causes plates to move
