Answer:
(1)Human cheek cells have a lining of flat and polygonal cells with irregular boundaries,which are arranged edge to edge.As a result,they seem to form a delicate sheet or lining of cells.
(2)They do not have cell wall,plastids and big vacuoles.
Answer:
1)Species are separated from one another by prezygotic and postzygotic barriers, which prevent mating or the production of viable, fertile offspring.
2)Speciation is the process by which new species form.
3) It occurs when groups in a species become reproductively isolated and diverge.
Explanation:
Nearly all of the energy that drives an ecosystem comes from the sun in the form of solar energy. Solar energy enters the ecosystem through a process of photosynthesis that is the starting point for all forms of plant and animal life on the planet. The sun and solar energy are the beginning source of energy for almost all functioning ecosystems and organisms on the planet.
Answer: Grey whales travel 12,000 miles round-trip from their feeding grounds in the Arctic to calve and breed in the Baja lagoons, and then back again.
Explanation:
