"An organism in which the two copies of the gene are identical — that is, have the same allele — is called homozygous for that gene. An organism which has two different alleles of the gene is called heterozygous."
Answer:
If limestone reacts with limestone, it can turn into a limestone. The reason behind this formation is that, both substances have the same chemical and physical properties and molecules of limestone have a strong chemical bonds between them so it is difficult to separate them from each other.
Robert Hooke observed the cells through a combination of lenses.
After Robert Hooke, the development of microscopy take place. After the development of the microscopy, scientist were able to observe the features of the cell. In order to formulate a cell theory observation of most of the cells was necessary. So, it was necessary to observe different types of cells from different organism. So, the advancement of the microscopy and observation process required for the formulation of the cell theory was the reason for the delayed development of the cell theory.
"Water quality" may include the amounts of dissolved oxygen
and the levels of algal growth, pollutants which may be present and the pH level. Water quality effects also which types of organisms can
survive in a body of water.
Shellfish require a high level
of dissolved oxygen and their abundance is an indication of good water quality. Shellfish are sensitive to changes in the ecosystem and they cannot easily escape changes in the water quality. These are one of the reasons why shellfish are good indicators of water quality.
Lawn and farming fertilizer is harmful to the enviroment due to the abundance of chemicals. When it rain or seeped underground, the fertilizer leaked into the nearby lake and thus, all the fish died to the chemicals in the fertilizer.
