Helper T cells are very important cells in the adaptive immunity. They are required for almost all adaptive immune responses and They also help activate cytotoxic T cells and macrophages to attack infected cells.
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Biodiversity decreases, and the overall health of the ecosystem decreases.
Answer: Option D
<u>Explanation:</u>
In a niche when two different species occupy a niche competition arises between them. In due course both the species fight for existence and nature selects the best adaptable one to win. The other species either reduces in its population or gradually in struggle for existence they deteriorate and die.
Hence a decrease in bio diversity happens here due to natural selection. If the biodiversity is decreased in a particular niche it affects the growth of different species which in turn affect the whole ecosystem resulting in decrease of the overall health in an ecosystem.
Answer:
c) The presence of an ephiphyseal line
Explanation:
The options should be:
a) the presence of osteoblasts
b) the presence of osteons
c) The presence of an ephiphyseal line
d) the presence of hyaline cartilage on the ends of the bone
Explanation:
In vertebrates, the epiphyseal line is formed once the bone is completely grown. This occurs inside a plate known as the epiphyseal plate.
From the age of 18 to 21, the bone stops growing and the cartilage inside this plate gets replaced by bone. However, bones can keep growing in width until we are approximately 25 years old.
Therefore, the physical sign that indicates that a bone cannot continue longitudinal growth would be the presence of an ephiphyseal line.
I would say C.nervous system because that pretty much defines all of the answer choices.
The answer is C I don’t think this needs more explanation but if needed just ask!