Electrons are passed to oxygen through a chanin of carriers in the inner mitochondrial membrane.
a. photorespiration
b. mitochondrial respiration
c. both

b. Mitochondrial respiration

Explanation:

Mitochondrial respiration of plants involves the participation of two major electron transport routes:

1. Cytochrome c oxidase route: cyanide sensitive and coupled to three energy conservation sites.

2. Cyanide-insensitive alternative route: involves alternative oxidase (AOX), branches off the cytochrome oxidase route into the ubiquinone pool, with no energy conservation thereafter as AOX is able to directly oxidize ubiquinol and reduce oxygen to water.

Regardless of the route followed, mitochondrial breathing is a long and complex process. However, it is through this breath that at a given moment electrons are passed to oxygen through a carrier channel in the inner mitochondrial membrane.  This happens when cytochromes to and some molecules that have a heme group (with an iron atom) and are linked to a transmembrane protein that connects the matrix to the mitochondrial intermembrane space and have two copper atoms that allow the transport of electrons to the final acceptor, oxygen (O2).

b.

they had the law tat factories that produces smoke cannot be built near residential buildings.

building of proper sewage system was done to ensure that the waste is carried away from the humans so that they do not get diseases from it.

also they built water systems to provide water in those areas which are drought prone.