Answer:
notochord, a dorsal hollow nerve cord and pharyngeal slits.
Its B clearing and farming. Because if you think of it when someone clears trees and bushes they most likely won't come back.
Answer:
Its Euglena
Explanation:
Shape change from normal elongated egg-shape to round-shape in stressful environment. These shape changes attain two transition phases. The I-transition phase is reversible where the organism can return to normal if favourable environment persists.
Answer:
Explanation:
The rate of pollination in the field (near the pond with no fish) will decrease exponentially. Because, as the fish population is removed from that ecosystem, the population of dragonflies and larva increases without check because, fish feeds on the dragonflies larva and kept there population in check. Due to this, the population of bees and other pollinators population decline becuase, they are major food source of dragonflies.
Honeybees are the keystone species because it's absence will lead to major changes in the ecosystem.