Properly identifying each species.
Accurately recording his findings.
Not interfering with ecosystem while studying the birds.
I would think it would be a worm virus considering that this is a biology question.
Answer: The theory of cheek cells is used for the identification of cheek cells.
Explanation:
The cells of cheek do not have cell wall. They have a cell membrane which allows on certain molecules to pass through it. The nucleus is located centrally in the cheek cells and it stores the DNA. It can be stained with the help of the methylene blue reagent. It appears blue in color which can be observed under the microscope. The cheek cells can be isolated from the buccal cavity by using cotton buds and cotton swabs can help in isolating the cells.
The study of one type of evidence of evolution is called embryology, the study of embryos. An embryo is an unborn (or unhatched) animal or human young in its earliest phases
So the answer is basically EMBRYOLOGY
Nondisjunction
DNA replication duplicates every strand of DNA so that there
are two copies of every chromosome. These (attached) copies, called sister chromatids,
undergo two rounds of chromosomal divisions ( Meiosis I and II). A total of
four haploid cells are now present. Homologous chromosomes or sister chromatids
are pulled apart in a process called disjunction. However, chromosomes may at
times fail to separate properly. This is called nondisjunction.