Answer:
A. True
Explanation:
Most viruses have either RNA or DNA as their genetic material. The nucleic acid may be single- or double-stranded. The entire infectious virus particle, called a vision, consists of the nucleic acid and an outer shell of protein. The simplest viruses contain only enough RNA or DNA to encode four proteins.
The population of frogs would exhibit competition due to the limited resources in the lake. Competition can be defined as the interaction among the species of organisms when resources are limited in an ecosystem. The type of competition observed in the above example of the lake with limited resources is called intraspecific competition as it is between the members of the same species competiting for the same resources. The species that do not compete will eventually die or get eliminated. This results in the change of population of frogs over time. Thus, competition is one among the forces that is responsible for natural selection.
If you are checking a cell for a zero value and the cell is blank, the test evaluates to true. For example, if you have the following formula in cell A1 =IF(B1=0,"zero","blank") and B1 is blank, the formula returns "zero" and not "blank" as expected.
If the range might contain a blank cell, you should use the ISBLANK function to test for a zero value, as in the following example: =IF(ISBLANK(B2),"blank",IF(B2=0,"zero","other")) Note that the above formula returns "zero" if there is a zero value in the cell, "blank" if the cell is blank, and "other" if anything else is in the cell.
You must always use the ISBLANK formula first before you test for a zero value. Otherwise you will always return a "true" for the zero value, and never get to the test for the ISBLANK formula.
