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.
<span>The answer is : Both have true necks, while eusthenopteron has no neck. </span>We know that tiktaalik is more closely related to acanthostega than it is Ichthyostega eusthenopteron because Tiktaalik and Acanthostega both have true necks while eusthenopteron has none.