Answer:
The correct answer is -Sponges lack true tissue but have morevariation in cell type than animas in oter phylum.
Explanation:
Sponges are belong under phylum porifera which have diverse form encrusting sheets to volcano shaped mounds.
The tubes that contain in their body are differ in size from millimeter upto one meter.
The poriferans contain canal system and with help of this, they pump water which enters through a specialed pores called ostia that flows through canal called spongocoel and finally the water exits from their body through oscula.
The sponges show complex organization as their body contain single tube with 2 cell layer thick.
Ascon,leucon,sycons are the level of complexity.
Viruses have not a nucleus, but they have viral DNA that they can transplant into other healthy cells to infect them.
Ans.
A nerve is defined as a bundle of axons. Axons are slender, long projections protruded from neurons in PNS (peripheral nervous system). The nerves provide a pathway for the transmission of electrochemical nerve impulses from axons to the other peripheral body organs.
Thus, the correct option to be fill in the blank is 'bundle of axons.'
Answer:
The radial symmetry animals get information through their receptor cells and neurons present all over their body.
Explanation:
Radial symmetry animals can be cut in different directions. The central axis separates it into 2 equal halves and again it can be cut into 4 directions.
e.g. Hydra, sea urchin, starfish, etc
They are invertebrates have sense organs, but these sense organs are not well defined. Each symmetry of the body has sense organs. These radial symmetry organisms have oral and aboral parts.
Sea urchins, starfishes, Hydra are light sensitive. They possess photoreceptor cells in their epithelial linings. Starfishes also sensitive to touch, light, and temperature. Their spines and tube feet have motor nerves, which control their movement.
Eyespots in starfishes also help in detecting objects. It is composed of epithelial cells and responds to light. They lack a brain but have a complex nervous system. This nervous system consists of a sensory nerve and motor nerve. It spreads all over the body. Hence starfishes can react according to the stimuli.
Answers:
a. We will see DNA fragments with 145-200 bps (only one band)
b. The DNA sequence linked to histones will be protected from the action of DNase I, thereby this enzyme only can cut linker DNA (i.e., 55 bp fragments). In consequence, it is expected to observe a single band with a length of approximately 145 to 200 base pairs
