The difference between analog and digital signals is that an analog signal is a continuous electrical message while digital is a series of values that represent information. Analog is conveyed by electrical current variations.
The answer is B. Cnidarians
Cnidarian body has no left or right side, only tom and bottom surfaces. If you divide cnidarian a about central point, you will get equal parts. So, cnidarians are radially symmetrical animals. This group includes hydroids, jellyfish, anemones, and corals. In all groups, animals have stinging cells on tips of tentacles. They use them to capture the prey. Their name literally means stinging creatures.
Ecosystem services are the benefits to people from nature. These benefits include food, water purification, carbon sequestration, soil stabilization, recreation, cultural values, among others.
The world's ecosystems are necessary capital assets due to the ecosystem services and the biodiversity they provide.