Answer:
nuclear fusion
Explanation:
When the density and temperature at the core of the gravitationally collapsing nebula reaches values when nuclear fusion is triggered and sustained, that marks the birth of the star.
When exercise does not increase bone mass, it has been observed that the risk of bone fractures increases due to osteoporosis.
<h3>What are the benefits of exercise to bone mass and density?</h3>
Bone mass refers to the mass of the bones in a living organism as a result of the deposition of minerals within the bone.
An increase in bone mass is directly related to the strength of the bone.
Strong bones have high bone masses whereas weak bone have low bone mass.
Physical activity have been shown to improve bone mass by increase the mass of deposited minerals in the bone.
Exercise such as walking, running, jogging, and other forms of exercise have been shown to improve bone mass and hence, the strength of bones.
However, when exercise does not increase bone mass, osteoporosis is observed which results in bone fracture.
In conclusion, the strength of a bone is directly related to the bone mass which is directly related to the mass of minerals deposited within them.
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This is because of B. Their cells are in direct contact with the environment.
Morphological character such as leaf, node density , bud number,etc. change in many plant species in response to factor such as light availability , soil compaction and organic matter removal.
Vegetative and reproductive characteristics are the two systems are common to nearly all vascular plants and provide a unifying theme for the study of plants morphology. It is important for the role to identifying plants, classification is also done by knowing the morphology of the plants.
Morphology is to identify plants using morphological characteristics. Plants can be identifies by observing certain distinguishing morphological characteristics but some plants are closely relatable , by which it shown by the similarity of their flower structures.
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