From other organisms such as plants and animas that eat plants or decompoers
Answer:
Constant variables
Explanation:
Elaina's investigation lacked the critical ingredient of constant variables which are important components of every scientific investigation. In every research, there are 3 important variables, namely:
1. Dependent variables: the actual variable to be measured during the course of investigations and whose values are dependent on another variable (independent variable) supplied by the investigators.
2. Independent variable: one of the variables that are supplied by investigators whose values are often manipulated to see the kind of changes it will cause to the dependent variable.
3. Constant variables: other variables that are neither independent nor dependent but constant for all the various experimental groups in investigations.
I'm fairly sure it's nitrogen and oxygen. Hope this helps.
<span> parathyroid hormone (PTH) </span><span>increases osteoclast activity to release more calcium ions into the bloodstream.
In short, Your Answer would be Option C
Hope this helps!</span>
I think both are A I’m not sure