When Pedro spent a year in the United States as an exchange student, he found that at first he seemed to make a lot of mistakes in the way that he dealt with people,
could explain why his classmates didn't understand why
he stood so close to people when he spoke to them.
А. A difference in the cultural display rules
В. Their indifference toward Pedro
С Petro's exposure to Western culture
D The school's lack of social activities

The correct answer is - option A. A difference in the cultural display rules.

Explanation:

Social or cultural displays rules are a social cluster or group and informal cultural norms to express their emotions in the correct way which are specific to cultural or social groups.

Pedro is an exchange student which makes his social norms different than the social norms or cultural display rules which cause difficulties to deal with the people and classmates.

step 1: nitrogen fixation- conversion of atmospheric no₂ into forms useful to plants by lightning, bacteria, and cyanobacteria.

step 2: nitrification-process of converting ammonia to nitrite or nitrate.

step 3: assimilation-plant roots absorb new form of nitrogen.

step 4: ammonification-conversion of organic nitrogen to ammonia by bacteria involved in decomposition.

step 5: denitrification-bacteria turns the decomposed matter back into n₂o, which is released into atmosphere; repeat cycle.

the answer is z.

the human body has five levels of organization. level 1: cells. cells are the basic units of life and form the first level of organization. cells in the human body have specific functions. examples include nerve cells, blood cells, liver cells, and so on.