Answer:
Bullock cart
Explanation:
Bullock cart is an ancient means of transport which is still used in many places of world. Bullock cart is a two wheeled or four wheeled vehicle that is pulled by oxen.
Oxen are also used for ploughing. they carry plough in their back and the person directs the plough in the right direction.
Hence, the correct answer is "Bullock cart".
Answer:
D. all the sunshine in a lake
Atmosphere.
Hydrosphere.
Biosphere.
Cryosphere.
Lithosphere(also referred to as the Geosphere).
The best answer in this case is C, "the researchers applied creativity to solve a problem in running an experiment".
Distributing the computing load across the global community by sharing processing power is a creative response to tackle the challenge in simulating protein folding for the experiment. This does not change or reduce the scientific merits of the experiment, so we can discount the first two answers (a & b). Answer d talks about well established scientific techniques, although the question wasn't really centered around the specific techniques, so it's not as relevant an answer as C.
The mechanisms of reproductive isolation prevent the reproduction of two individuals from different species. The prezygotic mechanisms disrupt the stages of reproduction before the forming of the zygote or prevent the mating at the start, and the postzygotic mechanisms affect the stages of reproduction after the forming of the zygote.
So, the first and the third example (the urchins and the grasshoppers) show the prezygotic mechanism, as the two individuals are not able to mate or form a zygote.
The second and the fourth example ( zonkey and the death of a zygote) show the working of the postzygotic mechanisms, as the zygote is formed, but it seems to be inviable, and the zonkeys are sterile, preventing the individual to reproduce.
