Dyad is the word to match your description
he outer core of the Earth is a liquid layer about 2,260 kilometers thick. It is made of iron and nickel. This is above the Earth's solid inner core and below the mantle. Its outer boundary is 2,890 km (1,800 mi) beneath the Earth's surface.
The answer is dusk and dawn.
Crepuscular animals are active during twilight (latin crepusculum). Twilight is a period after dawn and before dusk, so crepuscular animals want to avoid dusk and dawn. Animals' activity in different periods during the day depends on temperature or other biotic factors. It also depends on predators' activities or local competition.
In general, Yes True <span />