Answer: Farming
Explanation: Plowing the land is the first source of wealth.
Answer: Alveoli
Explanation: Alveoli of lungs are surrounded by extensive blood capillaries. The partial pressure of oxygen in the alveoli is higher than the blood entering the pulmonary capillaries, hence oxygen moves into the blood. Carbon dioxide in the lungs simultaneously diffuse out of the blood into the alveolar space.
Answer:
But what does “waxing and waning gibbous” mean? Rob says crescent is when you can see less than half of the moon illuminated. “Gibbous, you attach that to either waxing or waning when you see more than half of the moon illuminated,” he said. Waxing means it's getting bigger while waning means it's getting smaller.
Answer:
The correct answer is D
Explanation:
The cell membrane is essentially composed of the following:
- phospholipids
- cholesterol
- proteins
The phospholipid consists of a <em>hydrophilic </em>phosphate 'head' and the tail is the <em>hydrophobic</em> fatty acid chain.When cellular membranes form,phospholipids collect into two layers in light of these hydrophilic and hydrophobic properties. The phosphate heads in each layer face the fluid or watery condition on either side, and the tails conceal away from the water between the layers of heads, since they are hydrophobic.
There are 3 main factors that greatly influence the fluidity of the plasma membrane:
- temperature
- cholesterol
- saturated and unsaturated fatty acids
Answer:
The correct answer will be- true and structural specializations
Explanation:
The evolution of life on earth has suggested that life has moved from the simplicity to complexity or from single-celled organism to multicellular organism.
This multi-cellularity is achieved through the property of called cellular differentiation and specialization. as the cellular complexity increases, therefore, cellular demands like the use of energy, food, water and other variables increased.
This lead to the formation of the organ and organs system specializes to perform specific functions like the digestive system and another biological system.
Thus, true and structural specializations are the correct answer.
