Please choose the correct ending to complete the given sentence: Home and Garden: [header] How to detect flea bites [title] Familiarize yourself with what fleas look like. [step] Fleas are very small insects. They do not have wings and are usually brownish or reddish in color.

Ending1: They tend to be fleshy on the skin that usually has a crusty appearance. They can be as large as dogs, as little as a foot in length, as small as calves, and as huge as an elephant. Ending2: If you haven't been vaccinated, however, fleas might appear as unnoticeable specks of black on your skin. Mole fleas usually migrate from the top of your head to the nape of your neck. Ending3: These insects have flat-shaped bodies with a mouth and sharp jaws. Their flat bodies enable them to move easily through an animal's fur. Ending4: Most fleas can and do have a stripe directly across their thorax. They can also shed an excess of hairs on their bodies.

Answer format: ending1/ending2/ending3/ending4