Where might animals fit into to the photosynthesis/respiration cycle ??

Animals perform cellular respiration.

Explanation:

As plants release Oxygen through the process of photosynthesis, animals use this oxygen (as well as other inputs) to perform cellular respiration which releases Carbon Dioxide. Cellular respiration helps animals get the energy from sugar converted into more simple molecules such as ATP (Adenine Triphosphate).

Not suitable for animals, animal exercise consumes a lot of energy

Explanation:

 As you cannot do controlled crosses you need to have a lot of data from different family groups and compile recombination frequencies for these across numbers of these using statistical methods. You can also use markers such as microsatellites  which are easily scored.