internal-organ function, breathing, digestion, and heartbeat. This system consists of two complementary parts: the sympathetic and parasympathetic systems.
A solid minute object that is said to come together for the formation of the planet and are believed to produce cosmic dust are called planetesimal.
The options that best describes the planetesimals are:
- Option A. They are the origins of planets.
- Option B. They formed from gas and dust.
- Option D. They are believed to have developed in debris disks.
The descriptions can be explained as:
- It is believed that planets formation occurred through planetesimals. The formation happened from gas, dust particles and debris.
- By the process of accretion, the discs coalesced and became bigger and solid over time. This bigger mass started attracting other matters towards each other because of gravitational force.
- This pull resulted in either breaking or creation a bigger mass of pieces known as planetesimals. The collision continued to become bigger and solid planets we know today.
Therefore, options A, B and D are correct.
To learn more about planetesimals refer to the link:
brainly.com/question/10337322
Answer:
The ligand has only one receptor that it is able to bind to
Explanation:
The shape of the ligand and its corresponding receptor allow there to be specificity. For example, receptors for ligand A would be found on the target immune system cells and not on cardiac muscle cells or skin epithelial cells. Therfore, even though the cardiac muscle cells or the skin epithelial cells would be exposed to ligand A, they would not be able to bind to it and therefore could not react because of the specificity of the receptor of ligand A at that moment