I'm assuming you mean the molecular compound

and it's name is Hydronium. Hope this helps :)
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.
Answer: It can decrease or increase a population of species.
Explanation: Limiting factors include the availability of food, water, shelter, and etc. When a population of species are limited in any of these, they either move or adapt to their environment. So, population tends to decrease. The population that may finds an abundance of resources will find that their numbers tend to increase. This cycle is repeated over and over again.
Hope this helps!!!