<span>It began with selective breeding in the ancient times where a population with desirable traits were bred with other population to achieve a desired set of traits. It then continued with the advance in the discovery of bacteria (Escherichia coli) and antibiotics. Then Watson and Crick discovered the structure of DNA. The latest advance being that of gene sequencing and gene editing tools. </span>
b)1 unicellular- means one cell
Our skin cells divide rapidly in order to maintain a protective barrier against infection.The outer skin layer is called the epidermis and contains mostly dead cells that contain keratin.Keratin is a tough fibrous protein found in hair,skin and calluses and acts as a protective coating.The epidermis cells are constantly undergoing mitosis so the outer dead cells containing keratin are rapidly replaced as they fall off, which occurs after so many days.Then the newer living cells start producing keratin,lose their cellular contents,then die and the cycle goes on.The skin acts as a barrier to infection,therefore,it's constantly renewed and repaired.
Answer:
9
Explanation:
The diploid chromosome number for a radish is 18 and the diploid chromosome number for cabbage is also 18. The haploid number for these species is nine. Therefore, the gametes of the radish and cabbage contain nine chromosomes.
