Chromosomes *<Tab/>Most cells have a nucleus with a certain number of chromosomes. *<Tab/>There are twenty-three different pairs of chromosomes in human cells. *<Tab/>In females, each chromosome in the twenty-three pairs, appears to be identical to its partner. *<Tab/>In males, one pair is different, one chromosome is shorter than its partner. These two chromosomes are the …
showed first 75 words of 4025 total

showed last 75 words of 4025 total
…of a food web by the seashore: Pyramids of number and biomass Food chains and webs show the flow of materials and energy in habitats but they do not give you any idea of how many organisms there are in the habitat. To show this you need to draw a pyramid of numbers. Look at this example of a food chain. 2000 grass plants 25 voles 1 barn owl The pyramid of numbers would be as shown here.