Nope. Bastian mimicry is when a harmless organim disguises themself as a harmfull one. As for describing a stick bug I beleive the word you're looking for is camoflage.
When two sea caves on opposite sides of a headland are eroded and unite a sea arch forms.
Sea arch is a natural opening and a type of erosional landform that forms due to different rates of erosion, usually as a result of different resistance of bedrock. Sea arch is made up of a soft rock that eroded as waves hit land which creates caves in the rock. Two caves may become jointed over some time to form a tunnel and eventually, a sea arch.
Ans. (D). community.
In an ecosystem, a community can be defined as a association or group of organisms of two or more species that occupy the same region, in a particular time. For example, grasses, herbivores (such as deer), and carnivores (such as lion represent a community in a grassland ecosystem that affect each other.
As earthworms and robins belong to two different species, they will represent a community in a beech forest ecosystem.
Thus, the correct answer is option (D).