As the human population grows, the size of cities increases. As cities grow, more land must be cleared to make way for homes, businesses, and roads. Which two events would be likely effects of replacing a forested area with an urban area? A. More air pollution because there are fewer trees to take in carbon dioxide B. Less erosion of soil as plants covering the ground are added to gardens C. Fewer birds and other wildlife because they have fewer places to live D. More trees because of increased solar energy in the area

1. Introduction

The main air pollutants are represented by gases forms, particles in suspension, different ionizing radiation and noise.

The gases forms are: oxidized and reduced forms of carbon (CO2, CO, CH4), of nitrogen (NO2, NO, N2O4, NH3, NH4+), SO2, O3, C6H6 vapours, Hg, volatile phenols, Cl2, etc.

The particulate forms are: PM10 and PM2.5 particulate matter, heavy metals with toxic effect (Pb, Ni, Cd, As), polycyclic aromatic hydrocarbons PAHs, etc.

Atmospheric pollutants have a negative effect on the plants; they can have direct toxic effects, or indirectly by changing soil pH followed by solubilization of toxic salts of metals like aluminum. The particulate matters have a negative mechanical effect. They cover the leaf blade reducing light penetration and blocking the opening of stomata. These impediments influence strongly the process of photosynthesis which rate declines sharply.

Explanation:

A More air pollution because there are fewer trees to take in carbon dioxide

C Fewer birds and other wildlife because they have fewer places to live

Explanation:

I took the test on A P E X

it is the most commonly accepted one

the enthalpy of formation of water is given as -285.8kj/mol, which states that the enthalpy of formation is negative.

negative enthalpy of formation indicates that the heat is released during the reaction process. the heat is released from reaction to the surroundings the enthalpy is expressed with a negative sign with the energy given out in the reaction process.

the formation of water takes place by giving out heat which is -285.8 kj/mol.