Answer:
The correct option is A. they evolved from land mammals.
Explanation:
Evolution can be described as a process through which organisms in a species change over a period of time due to the natural selection of the environment. Those organisms that have many similarities in their functions or structures are considered closer to one another and have the same common ancestors.
The properties mentioned in the question about cetaceans resembles the properties of land mammals. For example, cetaceans lack gills and breathe air. Land mammals also do not have gills and need to respire for living. The cetaceans have fin bones which are similar to the limb bones in the land mammals. Hence, these observations show that cetaceas have evolved from land mammals.
<span>a. is continuous in two directions until the whole chromosome is copied.
</span><span>The two identical daughter cells resulting from mitosis and cytokinesis are identical in the following ways:1. Mitosis occurs when the nucleus of the cell divides into two identical nuclei, each with the same type and number of chromosomes. The cell's DNA is duplicated during this phase. Sometimes the cell's DNA isn't copied properly resulting in cancer-type cells. 2. Cytokinesis is when the cytoplasm divides into two identical daughter cells. Each cell is genetically identical and both are a similar size. </span>
Answer:
The study of oceans and their life.
Explanation:
The study of oceans, including seawater, the ocean floor, and marine plants and animals.
Answer:
The sodium-potassium pump is an active transporter because it needs to move sodium and potassium ions against the concentration gradient.
Explanation:
You have to think of it as outside vs inside the cell.
Outside the cell, you have 5mM K and 150mM Na. Inside the cell, you have 100mM K and 10mM sodium. Without the transporter then the ions would go from greater concentration to lower concentration. Energy keeps the ions going from the way they would naturally happen.
After two half-lives or 60 years, 7.5 g of the element will be left.
<u>Explanation:</u>
<u>Half-life:</u>
- In simple words, Half-life can be defined as the amount of time needed for a quantity to fall to half its value as contained at the beginning of the time period.
- In this problem the half-life of the element is thirty years, then after thirty years half of the sample would have decayed and half would be left as it is.
- After thirty years (The first half-life ) 30 /2 = 15 g declines and 15 g remains disappeared.
- And after another sixty years (The two half-lives) 15 /2 = 7.5 g declines and 7.5 g remains disappeared.
- After two half-lives or 60 years, 7.5 g of the element will be left.
