Fig. 1 shows a woodland food web close to a public footpath. Oak trees produce acorns. Wood mice eat acorns, tawny owls eat mice, and foxes can eat both mic...

Fig. 1 shows a woodland food web close to a public footpath. Oak trees produce acorns. Wood mice eat acorns, tawny owls eat mice, and foxes can eat both mice and owls. In autumn, volunteers counted acorns in sample squares and recorded wood mouse droppings as an estimate of mouse activity. They want to know whether a year with poor acorn production could affect predators. The woodland also contains decomposers that return mineral ions to the soil for plants.

(a) Use Fig. 1 to state one organism that eats wood mice. [1]
(b) Describe the relationship between acorn number and mouse-dropping number in Table 1. [2]
(c) Suggest why a low acorn year could reduce tawny owl breeding success. [2]

Fig. 1 shows a seal pup on a rocky shore. Its mother feeds at sea and transfers energy to the pup in milk. The pup has a thick layer of fat under its skin. Researchers measured the pup's mass every five days without separating it from its mother for long. They also recorded air temperature. During one period, storms prevented the mother from feeding for two days. The pup remained on land and used stored food molecules in respiration.

The pup's mass rose from 18.0 kg to 21.5 kg while its mother fed regularly. After the storms, its mass fell by 0.8 kg. The researchers did not conclude that all mass change was fat because water content can also change.

(a) What substance in milk can provide energy for respiration? [1]
(b) Describe the mass change while the mother fed regularly. [2]
(c) Suggest why the pup's mass fell during the storm period. [2]