I just found this by searching for "mushroom diagram".
neurotransmitters is the answer
The answer is D. Because the bird has to be noticed and the brighter the feathers the more likely the chance to be noticed.
Answer:
All four planets: Mercury, Venus, Earth and Mars are inner planets or also referred as terrestrial planets. Those are the planets orbiting closest to the Sun.
Earth is the largest of the Inner Planets, with a diameter of 12,756 km and Mercury is the smallest with a diameter of 4,878 km (3,031 miles). They have solid surfaces and thin/no atmospheres. Mercury is one of the densest planets in the Solar System. Venus is the brightest object we see in the sky, has a thick toxic atmosphere and is the hottest planet. Earth is the only planet that has liquid water.Mars surface contains iron-rich materials and has the most interesting terrain: the surface is very old and filled with craters.
Explanation:
The control is the group of no fertilizers.
A control in an experiment is usually the group without the variable to be tested. In this case, the farmer wanted to test the effects of fertilizers, therofre the group without it is the control group.