Answer:
The answer is the sun.
Explanation:
Level a represents the producers which you can tell, by their name, that they make their food. Producers are mainly comprised of the plants of our world. They get their energy from the sun and through photosynthesis, they turn it into energy.
By the way, B would be primary consumers which are the herbivores, C are the secondary consumers which include us people, and D are the decomposers, which include worms.
Human chorionic gonadotropin is secreted from the placenta. The correct option is D.
<h3>What is HCG?</h3>
HCG is known as Human Chorionic Gonadotropin.
It is a hormone secreted by the placenta during pregnancy.
The hormone specifically functions to thicken the wall of the uterus in order to be able to support the growing embryo.
It also signals to the body system to halt the process of menstruation.
More on HCG can be found here: brainly.com/question/23308035
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The tools used by marine scientists to make observations about oceans and marine organisms are Remote Operated vehicle (ROV), Automated untethered Vehicle (AUVs), Global positioning system (GPS) and Human-occupied vehicle (HOV).
<h2>Further Explanation
</h2>
ROV mean Remote operated vehicle which allows marine scientists to explore the ocean without necessary being in the ocean. Remote Operated Vehicle is a robot that is controlled by a person on the ship.
It is connected to the ship and the person that controls it uses joystick, which is similar to how we play a video game. It has a still camera, video camera and lights used to transmit videos and images back to the ship.
Automated untethered vehicles (AUVs) are untethered, unmanned vehicles that are used by marine scientists to conduct underwater research. Through Micromodem, an operator controlled computer passes information or command to AUVs in regards to when, where and what they sample. AUVs use different types of equipment for surveying and sampling such as sonar, camera and depth sensors.
Global positioning system (GPS) receiver is a navigation system that is used to show the location of the ship. GPS provides accurate navigation information for marine scientists.
Human occupied vehicle (HOV) also known as manned submersibles have the capacity to reach the full-depth of the ocean. It is used by marine scientists to carry out geophysical, geochemical, and biological studies, viewing and sampling of organism.
It has high quality video imaging system and can produce 3-D movies. It also has sophisticated syntactic foam.
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KEYWORDS:
- marine scientists
- marine organisms
- human occupied vehicle
- global positioning system
- remove operated vehicle
- Automated untethered vehicles
