Answer:
I think it's more man-made possibly, but it might be both. You might want to see if someone says both, both I guess C maybe.
1 C. 2. b 3,A 4A hope this helpps
Answer:
Explanation:
It's a normal part of nature, and one of many ecological factors that help keep the hundreds of thousands of living plants. It also keeps animals in balance with one another.
Answer:
OH, H2O2 and O−2
Explanation:
Reactive oxygen species (ROS) can be defined as highly reactive chemical compounds formed from molecular oxygen (O2). ROS are generated as a normal product of cellular metabolism, and also as a response to different environmental/internal cellular stimuli (e.g., cytokines, xenobiotics, pathogenic invasion). For example, hydroxyl radicals (·OH) are a type of ROS generated in the mitochondria which are capable of inducing oxidative stress in different cells and also trigger chronic inflammation. Moreover, hydrogen peroxide (H2O2) molecules represent another type of ROS which are produced during the stereoselective deamination of amino acids, i.e., the building blocks of proteins. These molecules (H2O2) exhibit toxic effects on the cell (e.g., DNA damage). Finally, singlet oxygen (1O2) is an excited state of molecular oxygen (O2) that is generated during photosynthesis in the photosystem II (PSII) of chloroplasts.
