Heifer – a cow that has not borne a calf, or has borne only one calf. In North America, a typical farm has about 100 milk cows and as many young female stock called heifers. The heifers are raised as replacement cows.
Impact crater is a type of impact landform formed due to collision of astronomical objects. Impact crater is a circular depression formed by the hypervelocity impact of a smaller body.Folowing are the examples of impact craters on the Earth:Lonar crater – IndiaKaali crater – EstoniaKarakul crater – Tajikistan