A. <span>A flatworm doesn't have a coelom
Flatworms and other invertebrates belong to a specific group called </span><span>acoelomate, wherein they lack a coelom and has an internal cavity which serves as their digestive cavity.</span>
The planet would be Neptune and Earth's average time is 365.2 days aka a full year (1 year).
Answer:
Osteoblasts
Explanation:
Cells that secrete protein fibres in bones are called osteoblasts.
I hope this helps.
The right option is; They allow the body to react to stimuli.
Nerve cells, (also called neurons) are specialized cells that are found in their millions in the nervous system. Nerve cells are created to stimulate other cells in the body. They transmit messages in the form of electrical signals within the body, and they allow the body to respond to stimuli. Neurons are grouped into three types which are; sensory neurons, motor neurons and association neurons.