Answer:
C. internal fertilization
Explanation:
The release of eggs and sperm into the water is known as spawning.
Answer: Subsistence agriculture.
Explanation: Subsistence agriculture is a type of farming in which farmers cultivate and grow food crops and livestocks to meet their needs and that of their family.
In this type of agriculture, farm products is aimed to survival and it doesn't involve use of large-scale irrigation, chemical fertilizer, or machinery and technology.
Inadequate dietary vitamin D or its deficiency leads to malabsorption of calcium. Nutritional disorder leads to the rare disease rickets, which causes bones to become soft and bend in children. In adults, vitamin D deficiency leads to osteomalacia, which causes weak bones, bone pain and muscle weakness.
The body needs vitamin D to properly absorb calcium and phosphorus from the diet. However, keeping the right quantities of calcium and phosphorus in bones is challenging when vitamin D levels are low.
The two sources of vitamin D are-
- Natural sunlight
- Foods such as fish oil, Egg yolk and fatty fishes like salmon and mackerel
There are other disease conditions which lead to poor absorption of vitamin D-
- Inflammatory bowel disease
- Celiac diseases
- Kidney problems
To learn more about Rickets here-
brainly.com/question/26292489
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