Answer: Paleozoic
Explanation: The Paleozoic Era, which ran from about 542 million years ago to 251 million years ago, was a time of great change on Earth. The era began with the breakup of one supercontinent and the formation of another plants became widespread. And the first vertebrate animals colonized land.
It means, process of eliminating waste matter..
Ionic compound means a metal bonds with a nonmetal.
<span>KBr Potassium Bromide, metal and nonmetal. (Ionic) </span>
<span>SO2 Sulphur Di-oxide, nonmetals (covalent) </span>
<span>FeCl3, Metal and nonmetal (Ionic) </span>
Answer:
The correct answer is:
Includes at least two groups, one of which does not receive the experimental treatment. (B)
Explanation:
A controlled experiment is made up of at least two groups of participants (subjects). One group (the test group) receives the experimental treatment, which can be an intervention or a new drug to be tested etc, and the effect of the treatment on the subjects is measured, while the second group of similar subjects also known as the control group acts as a baseline and do not receive the treatment or intervention. They act as a baseline to ensure that the change observed in the treatment group was brought about as a result of the treatment.
<em>Note that repeating the experiment several times does not ensure accuracy of the result, rather it ensures reliability of the results hence option D is not correct</em>
Answer: 3. gravitropism
The movement of plants in response to stimuli is called as tropism. Plants respond to different stimuli like light (phototropism), water present in the soil (hydrotropism), gravity (gravitropism) and touch (thigmotropism).
Gravitropism refers the growth and movement of plant parts with respect to the force of gravity exerted by earth. The roots shows positive gravitational tropism because they are growing towards earth gravity. The shoots or stems shows negative gravitational tropism because they are moving or growing against the gravity.