The answer is D optimistic
Answer:
There are extreme temperature variations, ranging from excessive heat to extreme cold.
Explanation:
Mercury being closest to sun gets extremely hot, but its "night" side (the side that is away from sun at a given time) gets very cold cuz mercury has no atmosphere to trap the heat.
Answer:
In this study, we tested the effects of NEAA-deprived diets and checkpoint inhibitor anti-PD-1 and anti-PD-L1 in colon cancer using syngeneic mouse model (Balb/c) bearing tumors of mouse colorectal cancer cell line CT-26. Three diets were tested, including a natural rodent diet Teklad ENVIGO Global 16% Protein Rodent Diet (control 1), a formulated NEAA-complete diet COMPLETE (control 2, using amino acid mix in place of protein), and a formulated NEAA-deprived diet FTN203 (treatment, using amino acid mix in place of protein). Both COMPLETE and FTN203 have the same nutritional structures, contain 17% w/w protein equivalent, and are isocaloric. After tumor size-based randomization, these diets were provided to mice ad libitum throughout the whole test. Each of these diets was used alone or combined with anti-PD-1 antibody (i.p., twice per week for 2 weeks) or anti-PD-L1 antibody (i.v., twice per week for 2 weeks).
Explanation:
Natural environment has the ability to gather some pollutants yet if too much then the environment could no longer handle it. A leaky sewage can pollute an aquifer with I. arsenic as the contaminant. Arsenic is a metalloid existing in the Earth's crush. Exposure is natural yet can be aggravated by the human activities.