The correct answer is (d). Bacteria are living organisms that are prokaryotes, meaning they do not have a nucleus or other membrane-bound organelles. They are single-celled and can be found in a variety of environments, including soil, water, and the human body. Bacteria are essential to the Earth’s ecosystem, as they play a role in the decomposition of organic matter and the cycling of nutrients. They are also used in a variety of industrial processes, such as the production of antibiotics and biofuels.
Option (a) is incorrect because bacteria are clearly living organisms. They are able to reproduce, grow, and respond to their environment.
Option (b) is incorrect because bacteria are not on the border line of plants and animals. They are a separate kingdom of organisms.
Option (c) is incorrect because bacteria are not on the border line of flowering and nonflowering plants. They are not plants at all.