Which organ system is responsible for regulating body temperature

Simplified it's actually many systems that work together, just in different ways!

Explanation:

A large part of the body that is responsible for the regulation of temperature is the nervous system. The hypothalamus, which is a portion of the brain, controls the regulation of body temperature. The process that allows the human body to maintain its core temperature is called thermoregulation. The hypothalamus sends signals to various parts of the body, such as the glands and nervous system, when its core internal temperature begins to fluctuate too high or low.

However, the endocrine and the excretory systems also play a role in the regulation of body temperature.

Hope this helped!

fertilization, pictured in figure 24.23a is the process in which gametes (an egg and sperm) fuse to form a zygote. the egg and sperm each contain one set of chromosomes. to ensure that the offspring has only one complete diploid set of chromosomes, only one sperm must fuse with one egg. in mammals, the egg is protected by a layer of extracellular matrix consisting mainly of glycoproteins called the zona pellucida. when a sperm binds to the zona pellucida, a series of biochemical events, called the acrosomal reactions, take place. in placental mammals, the acrosome contains digestive enzymes that initiate the degradation of the glycoprotein matrix protecting the egg and allowing the sperm plasma membrane to fuse with the egg plasma membrane, as illustrated in figure 24.23b. the fusion of these two membranes creates an opening through which the sperm nucleus is transferred into the ovum. the nuclear membranes of the egg and sperm break down and the two haploid genomes condense to form a diploid genome.

explanation:

the correct answer is option b

behavioral response need communication and thus co-ordination at several levels such as interaction among cells, organ system and the entire organism.

behavioral response produces both internal and environmental stimulus.