Answer:
In the 1960s, scientists found evidence that new material is indeed erupting along mid-ocean ridges. The scientists dived to the ocean floor in Alvin, a small submarine built to withstand the crushing pressures four kilometers down in the ocean. In a ridge’s central valley, Alvin’s crew found strange rocks shaped like pillows or like toothpaste squeezed from a tube. Such rocks form only when molten material hardens quickly after erupting under water. These rocks showed that molten material has erupted again and again along the mid-ocean ridge.
When scientists studied patterns in the rocks of the ocean floor, they found more support for sea-floor spreading. You read earlier that Earth behaves like a giant magnet, with a north pole and a south pole. Surprisingly, Earth’s magnetic poles have reversed themselves many times during Earth’s history. The last reversal happened 780,000 years ago. If the magnetic poles suddenly reversed themselves today, you would find that your compass needle points south.
Explanation:
I found this somewhere.
Answer:
c. the formation of bone from within fibrous membranes
Explanation:
On the basis of formation ossification process is divided into two types:
1) Endochondral ossification : The process by which bone is formed from haline cartilage.
2) Intramembranous ossification : The process by which bone is formed by replacing a fibrous membrane and not from cartilage. This type of ossification occurs as follows :
- An ossification center appears in the fibrous connective tissue membrane.
- Bone matrix is secreted within fibrous membrane
- Woven bone and periosteum forms.
- Bone collar of compact bone forms and red marrow appears.
Hence option c. the formation of bone from within fibrous membranes is the right option
Answer: The primary motor cortex for control of voluntary muscles is found in the precentral gyrus of the frontal lobes.
Explanations:
The primary motor cortex is one of the important brain areas involved in motor function. It is found in the precentral gyrus of frontal lobes. It control voluntary muscles and generate impulses needed for movement execution.
Voluntary muscles are muscles that we can control consciously or we can control them at will and we can choose when we want to use them. They are also refers to as skeletal muscles and are attached to bones. The are majorly use for locomotion.
Answer:
Explanation:Which characteristic of pea plants were important in their selection as ... Which statement below best describes the difference between mitosis and ... mitosis is the portion of the cell cycle that divides the nuclear material while cytokinesis divides the ... Animal breeders who discover a unique trait and selectively breed to
