Orcas, or killer whales, are natural predators of sea otters. it has been observed that in regions where the sea otters are not present, sea urchins grow rapidly and destroy much of the natural kelp vegetation.

which of these statements is correct in this context?
a) kelp is the keystone species because their survival is key to the survival of the entire ecosystem.
b) sea otters cannot be considered the keystone species because they are not the top predators in the ecosystem.
c) sea urchins are the keystone species because they multiply rapidly in the absence of their natural predators.
d) sea otters are a keystone species as they prevent a herbivorous species from completely destroying a plant species.

Plzzz hurry im being timed ! humans, like other organisms, require energy for growth and repair. when cells create atp for energy, carbon dioxide is produced as a waste product. how does the body respond to this process in order to maintain homeostasis? a. the digestive and respiratory systems interact to move carbon dioxide to the lower intestine, where it is transformed into methane. b. the circulatory and digestive systems interact to move carbon dioxide to the stomach, where it to break down food. c. the nervous and urinary systems interact to move carbon dioxide to the kidneys, where it is absorbed into the bloodstream. d. the circulatory and respiratory systems interact to transport carbon dioxide to the lungs, where it is expelled from the body.

What is the answer for the complicated molecules that make up living things usually contain carbon. why is carbon so important in these molecules?

Amale bird-of-paradise uses a dance to attract mates in which it flaps its tail feathers on the ground and jumps around a potential female mate. a different male bird-of-paradise does a similar dance but it jumps around the female in the opposite direction. the female bird is only attracted to one style of dance, in one direction. this is an example of speciation.