Why are small quantities of chlorofluorocarbons so harmful to the ozone layer?
a.
the chlorofluorocarbons act like ultraviolet radiation causing large amount of ozone to be produced.
b.
the chlorine from the chlorofluorocarbons reacts with free molecules of oxygen causing a stop in ozone production.
c.
free oxygen atoms can replace the chlorine in chlorine monoxide, releasing a free atom of chlorine which can then recombine with an oxygen atom in ozone, destroying more ozone.
d.
chlorofluorocarbons absorb ultraviolet radiation, preventing the formation of ozone.

Answer : Option C) Free oxygen atoms can replace the chlorine in chlorine monoxide, releasing a free atom of chlorine which can then recombine with an oxygen atom in ozone, destroying more ozone.

Explanation : Small quantities of chlorofluorocarbons are considered harmful to the ozone layer because the free oxygen atoms found in the ozone layer region gets replaced by the chlorine monoxide compound which releases a free chlorine atom in the atmosphere, which later get combined with the another oxygen atom which destroys the ozone layer. It makes the ozone layer more thin than before by this process.

before, trains worked using the steam engine. thus, it uses heat so it is crucial to apply heat balance. the steam engine absorbs energy during the stage of boiling water. so, this is the endothermic reaction. when the steam is used to work the piston, it has to release this energy through running the train. the excess energy is released as an exhaust to the chimney. this is the exothermic process because it releases energy to the surroundings.

the answers are as following:

1. c. double helix, nucleosome, coil, supercoil, chromosome

2. b. g2 phase, preparation for mitosis

3. d. interphase consists of the g1, s, and g2 phases

4. c. metaphase

5. a. chromosomes are duplicated before cell division so that each new daughter cell has a complete set