Because there will be no bias if the reasearcher knows which drug is being given and the subject wont know what they are being given so both may assume that the subject is going to feel happier and expect to have an elevated mood and relieve feelings of depression. Hope this helps :)
Primitive Plant is an example of a plant group where the male gametes depend on moisture to swim towards the ovum.
True since some of the input energy is turned into heat energy, which is then lost in the environment. This is why input work is never equal to output work, unless the problem is set in a 'perfect world'.
Answer:
Examples of abiotic factors are water, air, soil, sunlight, and minerals. Biotic factors are living or once-living organisms in the ecosystem. These are obtained from the biosphere and are capable of reproduction. Examples of biotic factors are animals, birds, plants, fungi, and other similar organisms.
Answer:
Pictures from Hubble help scientists learn more about the whole universe.
Explanation:
Hubble has helped scientists learn about our solar system. The telescope observes comets and planets. Hubble even discovered moons around Pluto that had not been seen before. The telescope has helped scientists understand how planets and galaxies form. Galaxies contain billions of stars. A picture called "Hubble Ultra Deep Field" shows some of the farthest galaxies ever seen. Because of Hubble pictures, scientists think the universe is almost 14 billion years old.