It has taken millions of years for the ancestors of whales to change into what we know today, as indicated in the diagram below. 60 million years ago
35 million years ago
Based on your knowledge of evolution, which of the following is a reasonable explanation of why the organisms in the diagram changed over the 25 million years?
A. As the environment changed the predators on land became better adapted to hunting the whales' ancestors forcing them to live in more aquatic environments.
B. As the environment changed the temperature became too hot and the organisms began to move to a more aquatic environment to keep cool.
C. As the environment changed the food sources became more difficult to obtain so characteristics that allowed the organisms to hunt in an aquatic environment
became more advantageous.
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D. As the environment changed the food sources became more difficult to obtain so the organisms decided to change their characteristics to ones that would be
beneficial when hunting in an aquatic environment.

cats ; snakes

when atoms of different types of elements join together, they make molecules called compounds. water consists of compound molecules made up of 2 hydrogen atoms and 1 oxygen atom. this is why it's called h2o. water will always have 2 times the number of hydrogen atoms as oxygen atoms.

interphase

the period of cell growth when the cell synthesizes new molecules and organelles. the cell is not dividing and it constitutes the majority of the time spent in the cell cycle

prophase

changes occur in the nucleus and cytoplasm. the chromatin condenses to form structures (sister chromatids) visible with a light microscope and the mitotic spindle begins to form, but the nucleus is still in tact

prometaphase

the nuclear envelope fragments and the spindle microtubules attach to the kinetochores of the sister chromatids

metaphase

all the cell's duplicated chromosomes are lined up at an imaginary plane equidistant between the poles of the mitotic spindle

anaphase

begins when sister chromatids separate from each other and ending when a complete set of daughter chromosomes arrives at each of the two poles of the cell

telophase

the daughter nuclei form at the two poles of a cell

cytokinesis

the division of a cytoplasm to form two separate daughter cells. usually occurs during telophase during mitosis. this and mitosis make up to mitotic (m) phase of the cell cycle

it marks things for degradation via the proteasome. it alters there celluar location.