A secondary source is anything written after the fact
Answer:
To show the flow of energy through ecosystems, food chains are sometimes drawn as energy pyramids. Each step of the pyramid represents a different trophic level, starting with primary producers at the bottom. The width of each step represents the rate of energy flow through each trophic level.
Explanation:
Answer:
Explanation:
The most primitive tool I used today was the hammer. The hammer is age long in the history of household tools. It is used to hit in nails into walls or woods.
The most advanced tool I have used today is the mobile phone. This is a tool of the 21st century which makes communication easier and faster.
I believe he is looking for an allele
An allele is a variant form of a gene. Some genes have a variety of different forms, which are located at the same position, or genetic locus, on a chromosomes. Humans are called diploid organisms because they have two alleles at each genetic locus, with one allele inherited from each parent.
