The order Cetacea includes modern-day whales, dolphins, and porpoises. These marine mammals share common characteristics that ha
ve led scientists to make a conclusion about their evolutionary history. Cetaceans: lack gills and must breathe air
give birth to live young rather than lay eggs
have fin bones that are similarly shaped to limb bones
have spines that flex up and down rather than side to side
The characteristics of cetaceans provide evidence that
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.
Leaves are the site of the food making process called photosynthesis. In this process, carbon dioxide and water in the presence of chlorophyll (the green pigment) and light energy are changed into glucose which is sugar. This energy rich sugar is the source of food used by most plants.
Because a gamma ray has higher frequency waves, and those high frequency waves contain the most energy. They have short wavelengths but high frequencies, therefore, because of those high frequencies, that is why it contains the most energy among them.
